Event Gyms are a new event that we added after the server update to 3.5.1.

Event Gyms are basically level 100 gyms that are supposed to be more difficult to beat than the regular gyms. Event gyms occur every 3 weeks and run for 1 week.

Event Gym Rules:

-Use level 70-100 pokemon
-No revives, potions, or other healing items
-No legendary pokemon
-Do not use the moves minimize or double team

Basically, the same rules as any regular gym.

The first, second, and third person to beat each leader of the event gym will get an extra pecial reward. Everyone who wins after that will get a special reward as well.

(If you want to know what the event gyms are/who the leaders are, there are leaders on pedestals with their gym names at /warp staffroom)

That's about all there is to say about Event Gyms :) hope this helped!