What Communities have you guys found that are worth joining?

I really hope after the Beta ends (in about six weeks) this place lasts the test of time. The ideas behind Imzy really appeal to me and hopefully if this place is properly moderated Imzy will remain largely nice place (unlike a certain website).

Anyways I'm curious what communities you guys have found (or founded) that are worth joining; as of right now my feed is pretty dead (which is to be expected) save for the Fempire so I'd like to find some additions so my feed can be a little more active.

Additional Question: just out of curiosity do you guys have any ideas for potential communities which you are considering founding or feel should be founded? The only community I'd particularly like to see made right now is one for Aspies.