I went to see Crash last week. I thought it was really, really good, but that might just be because I happen to live in Los Angeles, so I kinda "get" a lot of what happens in the movie. It basically follows several different characters of varying ethnic, social, and economic backgrounds, as their stories intertwine over a two day period in Los Angeles. There is a trailer and a clip of the movie over at
http://www.apple.com/trailers.
I'm pretty sure it's a limited-release kind of movie, only showing in the bigger markets, plus it's been out for about a month and a half now I think, so it may be hard to find. But if you see it playing somewhere, I highly recommend you go see it. Caveat is, it's not a "go with the family" kind of movie, and I would say that you'd have to at least be in your late teens to get much of anything out of it; besides, there's brief nudity, violence, and racial overtones throughout.
--edit: Oops, it seems apple doesn't have the trailer any longer. It is still on the movie's site,
http://www.crashfilm.com/, but I don't think the clip is anywhere now.