fanficrants : With near-constant updates and several years of old posts, this is always good for near-endless sources of hilarity.
ihasatardis : Level of entertainment described above, times twenty for less negativity.
office_meta : When it's, you know, not dead, this is the greatest concept ever invented.
polloftheday : Glee! POLLAGE. Random polls about everything.
whatwasthatbook : One of the few communities I actually include on my friends page, both because I can frequently help with the children's/YA books, and because it's an amazing resource - it's only failed me once in the year or so I've been using it.
I could probably come up with 15 more (oh crap, m15m !), but then I'd just feel worse about the remaining ones I didn't have room for, so first
P.S. In a completely unrelated note, OMG FLUFFBALL PUPPY. And now I'm going to...resume writing this cover letter. Yes. Because that's fun.