I got excited when fighting dungeon raids with my guild mates,doing solo dungeons,flushing the toilet (even if that excitement always disappears fast because items i get suck) and of course on days of epic,mushroom,gold or experience events
And yeah HoF of course.
Its good that in every ~50 Levels players can meet something new. New dungeons,collecting magic mirror,arcane toilet,the tower..etc..this keeps the game playable and not boring,we need more of those things