Events

Army Discount Events
From the 2016 Christmas Update on, there have been a continuous series of events in which players can train troops or brew spells at reduced cost for a limited time, although there were also several Events before that Update which didn't reward gems. The troop events function like mini-achievements, in which players need to win a certain number of multiplayer battles, each with a certain number of the said troops, to claim some Experience and Gems.

If not mentioned otherwise, the discount rates are 90% (or reduced to 10% of normal cost), and for each Event involving at least one troop, the number of wins required is 3, and rewards are either 100 or 300 Experience and 30 gems; the spell events are simply discounts.

Using the exact number of the said troops is not required; it's totally OK to use more than the number of the required troops, as long as at least one star is achieved. The troops in the Clan Castle also count for the number of troops, and are essential for players with lower Town Hall levels that can't train the said troops by themselves. If the Town Hall level is low enough such that neither training nor requesting the said troop is possible, a number will still be displayed, but the mini-achievement reward is unattainable (it's not beneficial to rush buildings). Also, players can aim for this reward and the Star Bonus simultaneously.

For multi-troop events, the reward for each troop is achieved separately, but players can aim for them simultaneously. The requirement for each individual troop is equal to the requirement of that troop's single troop event.

Below is a table about how many troops are needed in each type of event. For most troop events, players need to have at least one fifth of total space possible at the Town Hall level being that troop, the number of troops required are rounded to the nearest integer. If the Town Hall level is not enough to unlock the said troop, the requirement becomes filling as many as possible to the maximum level of Clan Castle at the Town Hall level.

*Only available as Clan Castle troops.

The Town Hall level might be the sole factor of the troop requirement, regardless of whether or not the Barracks or Dark Barracks (to unlock the said troop), s and the Clan Castle are at the maximum level possible at the TH level. For example:
 * A new TH 9 with two level 4 Dark Barracks still requires 4 Witches for the Witch Event, and is therefore locked outside of the reward without using a Book of Building. Had his Town Hall's upgrade not finished during the event, he would have been able to claim the reward by using two Witches as Clan Castle troops. Same goes for the Witch part of a multi-troop event.
 * A new TH 10 with four level 7 s requires 10 Balloons rather than 9 for the Balloon Event.

In all these events, players get a chance to gain some resources by queuing just before the end of the event and unqueuing after the event ends. Theoretically, an Event of 90% discount on Wall Breakers and Freeze Spells will yield the maximum amount of Elixir possible (1,490,400 ) and an Event of 90% discount on Witches and Earthquake Spells will yield the maximum amount of Dark Elixir possible (26,334 ). For multi-troop events, players can also choose to get a mix of both resources.

The Army Discount event almost always have an event challenge. The challenge requires you to use a certain number of discounted troops to win multiplayer battles with them. This includes revenge attacks, but does not include Versus Battles which take place in the Builder Base.

Note that the figures in the upcoming events are estimates and are probably different from the exact value.

The "Resources" column indicates the maximum amount of resources attainable by queuing and unqueuing. A lower value in parentheses indicates that the higher value can only be attained by instantly finishing some upgrade.

Dragon Events
*Town Hall 9 needed 3 Dragons and Town Hall 10-11 needed 4 Dragons in the first Dragon Event, which was an exception to the table. In the third event, Town Hall 7-8 required 2 dragons as well.

Valkyrie Events
*In the second Valkyrie Event, players needed to have at least one half (instead of one fifth) of total Army Camp space possible at the Town Hall level being that troop (13 for TH 8, 14 for TH 9, 15 for TH 10 and 11), which is an exception to the table.

Wall Breaker, Balloon, Witch and Skeleton Spell Event
*The discount rate wasn't fixed in this Event. Also, the maximum amount couldn't be reached due to the Event ending in a maintenance break.

Giant, Barbarian and Archer Event
*The requirements of each troop was only half the value in the table above.

All Troops Event
* Originally meant to last 7 days, but was extended by another 7 more days following a maintenance break.

One-Gem Collector Boost Events

 * During each annual anniversary of the game (late July to early August), players are able to boost each, and Dark Elixir Drill for 7 days with 1 gem. Normally, each player can boost each of his collectors for one round, but if they're not at the maximum level, he can choose to press upgrade and cancel and boost for a second round, but will waste half of the upgrade cost (especially for Dark Elixir Drills, which have high upgrade costs). However, in the 2017 Clashiversary event, one gem only boosted for 1 day instead of 7 days.
 * During each Christmas, players are able to boost each, and Dark Elixir Drill for 1 day with 1 gem, with the maximum number of rounds equal to the number of days in the event.
 * In the days immediately following the release of Town Hall level 12, players are able to boost all resource collectors for 1 day with 1 gem; this started at UTC 13:00 11/6/18 and was initially scheduled to last 7 days; following a maintenance break on 15/6/18, this event was extended by another 7 days.

One-Gem Troop Training Boost Events

 * During each Christmas, players are able to boost each Barracks, Dark Barracks and Hero with 1 gem. However, the gem boost "discount rates" vary in each year's event. A 7-day Valentine Hero boost event also started on UTC 13:00 13/2/17.
 * In the days immediately following the release of Town Hall level 12, players are able to boost all barracks and heroes for 1 hour with 1 gem; this started at UTC 13:00 11/6/18 and was initially scheduled to last 7 days; following a maintenance break on 15/6/18, this event was extended by another 7 days.

One-Gem Spell Brewing Boost Events

 * During each Halloween, players are able to boost the Spell Factory and the Dark Spell Factory with 1 gem. However, the gem boost "discount rates" vary in each year's event.
 * In the days immediately following the release of Town Hall level 12, players are able to boost both Spell Factories for 1 hour with 1 gem; this started at UTC 13:00 11/6/18 and was initially scheduled to last 7 days; following a maintenance break on 15/6/18, this event was extended by another 7 days.

One-Gem Donation Events
* Originally meant to last 7 days, but was extended by another 7 more days following a maintenance break.
 * During this event, the gem cost to instantly donate troops, spells and Siege Machines was reduced to one.

Builder Base Mega Marathon Event

 * During this event, the gem cost to instantly obtain the next set of Win Bonuses through Versus Battles was reduced to one third of its original value.

Clan XP and/or War Bonus Resources Events

 * Increased Clan XP and/or resources can be awarded if any part of a war lies in the interval of an event.
 * The first three Events were celebrating the first through third anniversaries of Clan Wars, respectively. If a Clan XP and/or War Bonus Resources Event lasts for n days, players are able to get a maximum of $$\Bigg\lceil{24n \over 47}\Bigg\rceil+1$$ wars with increased rewards during this event. The first event occurred before preparation lengths were shortened (during late 2015); the maximum number of wars with increased rewards during that event was 5.

Star Bonus Events

 * During the Star Bonus events, the Star Bonuses are multiplied by a factor. If a Star Bonus Event lasts for n days, players are able to get a maximum of n+1 increased Star Bonuses during this event, probably having to waste some "Star Bonus Time", but still beneficial to do so.

Builder Base Battlefest Events

 * During these events, players get Win Bonuses through Versus Battles every 8 hours instead of every 22 hours.
 * During the second and third event, players' Win Bonuses were also increased by 25% (the third Win Bonus has the same amount of loot increase, rather than percentage increase, as the first two wins).

Barbarian and Dragon Training Boost Event

 * From: 29/1/15 To: 5/2/15
 * During this event, Barbarians and Dragons trained 5 times quicker; the Barbarian's training time was reduced from 20s to 4s while the Dragon's training time (at the time) was reduced from 30m to 6m.

Hammer Jam Season

 * During this event, building and hero construction/upgrade times in both villages are reduced by half. Since this event reduces time rather than making the countdown twice as fast, this means: stacking with Builder Potion and Clock Tower boosts multiplicatively; fewer experience points are gained from constructions/upgrades; players can start constructions/upgrades when the event is almost over to save more time and still gain normal amount of experience.

Santa's Surprise Events

 * From: UTC 10:00 23/12/16 To: UTC 10:00 6/1/17
 * From: UTC 8:00 19/12/17 To: UTC 8:00 3/1/18
 * It's featured as 2016 and 2017 "Clashmas" gifts. See Santa's Surprise page for more information.

Freeze Trap Event

 * From: UTC 10:00 27/12/16 To: UTC 10:00 6/1/17
 * It was the second of three 2016 "Clashmas" gifts. See Freeze Trap page for more information.

Ice Wizard Events

 * From: UTC 10:00 30/12/16 To: UTC 10:00 6/1/17
 * From: UTC 8:00 23/12/17 To: UTC 8:00 3/1/18
 * It's featured as 2016 and 2017 "Clashmas" gifts. See Ice Wizard page for more information. Also, there was a mini-achievement during the 2016 event. Players needed to win three multiplayer battles, each with a certain number of Ice Wizards, to claim 300 Experience and 30 Gems.

Battle Ram Event

 * From: UTC 07:00 4/8/17 To: UTC 07:00 11/8/17
 * It was the first of the 2017 "Clashiversary" events. The event allowed the Battle Ram to be trained temporarily. Players winning ten multiplayer battles with at least a certain number of Battle Rams could claim 500 Experience and 250 Gems.

Giant Surprise Event

 * From: UTC 07:00 11/8/17 To: UTC 07:00 18/8/17
 * It was the second of the 2017 Clashiversary events. This event, while adding no new content by itself, temporarily changed the mechanics of the Builder's Hut to spawn a level 1 Giant whenever it was destroyed.

Shrink Trap Event

 * From: UTC 07:00 18/8/17 To: UTC 07:00 25/8/17
 * It was the third of the 2017 Clashiversary events. The event allowed players to place the Shrink Trap in their Home Village temporarily. See Shrink Trap for more information.

Birthday Boom Event

 * From: UTC 07:00 25/8/17 To: UTC 07:00 31/8/17
 * It was the fourth of the 2017 Clashiversary events. The event allowed players to temporarily brew the Birthday Boom spell. Players winning ten multiplayer battles with a certain number of Birthday Booms could claim 500 Experience and 250 Gems.

"Builder is Back!" Event

 * From: UTC 07:00 31/8/17 To: UTC 07:00 7/9/17
 * It was the fifth and final Clashiversary event. This event allowed players to use the Battle Ram, Giant Surprise and Birthday Boom once more; however no rewards could be obtained.

Trick or Treat (Pumpkin Barbarian and Giant Skeleton) Event

 * From: UTC 07:00 28/10/17 To: UTC 07:00 3/11/17
 * It was part of the 2017 Halloween Event. This event allowed players to use the Pumpkin Barbarian and Giant Skeleton for a limited amount of time.

Jack Skellingboom (Giant Skeleton) Event

 * From: UTC 08:00 28/12/17 To: UTC 08:00 3/1/18
 * It was part of the 2017 Christmas Event. The Giant Skeleton in the Halloween Event was available as a temporary troop for the second time.

Clan Games

 * Clan Games are a new type of event introduced in the December 2017 update. These Games introduce in-game tasks for the whole clan to try to complete.
 * For more information, see the Clan Games page.