So, I'm one of the admins on a large, online text-based roleplaying game (a MUX, for those who know these sorts of things). And earlier tonight we discovered our database was starting to go corrupt. This is a bit of a problem, because our database is 90 megabytes compressed. Luckily, to make a long story short, we were able to rollback only a tiny bit and the game was more or less intact except for minor things we could hand-fix.
Made for an interesting evening, but when these sort of things work out it can be one of the more rewarding experiences involved in being an admin on this sort of game. The playerbase really pulls in behind you during times like this, and it gives a real sense of community and comaraderie.