Wrath!
This may shock you but Aion Classic EU does in fact get routine updates and patches. Patch 3.7, Wrath, drops on April 23 and brings with it new challenges across a couple of dungeons.
The Burning Blood Fortress is first, a 6 player dungeon for players between level 56 and 60. Gameforge promises time-sensitive mechanics and solo trials within, that players can run five times weekly and obtain new weapons, wings, and stigmas.
Dokkaebi Realm is also for level 56-60 players with rewards of its own that can also be run five times weekly.