We went down for a few hours this morning. We're using pretty bleeding edge development tools on this site which is part of the reason we can crank out new features so fast.... well - one of those tools just bit us pretty hard. Apparently the code we're using for the new search stuff we put in last week is, um, not so stable. :)
So - we've pulled the new search stuff for now, put back in the old not-so-great search we used to have and will try to figure out why the new search stuff killed our server.
Sorry about the crash!