This idea is a little silly, and probably impossible to track, but maybe a trophy for spending time in the chat a lot? Like, if there was a way to track your logins and the time you spent there, you could get a 'You Survived!' trophy, for being in the chat and not pissing off the mods long enough to become a regular or semi-regular. This isn't really a serious thing, mostly a joke that was talked about in chat- but if there was a way to make it possible, I think that would be a cute one.
Also, for 2000 Likes: Y2K.