Via this post on Lorcan Dempsey's blog, I noticed that the Internet Movie Database now has genre keywords and tag clouds.
For example, library brings up a cloud where murder appears to be the largest tag. The list of films matching the chosen facet(s) is ordered by rating, so you get instant recommendations for whatever mood you're in.
It's also fun trying to guess which films might match multiple facets — 10 points if you can name a film that matches both "library" and "flame thrower" without looking!
Ghostbusters?
Fahrenheit 451?
The 10 points go to Rob