Doctor ooh...

Because I was out getting very drunk yesterday evening, I completely missed last night's episode of doctor who. Can someone nice tell me what happened, please?

note: I'm not an avid follower of the show (due to the fact I only seem to watch tv at other people's houses these days), but I've gathered form vairous other people's lj's and facebook updates that SOMETHING BIG HAPPENED, and now I really need to know what....