I reported yesterday about two spam sites that have billions of pages in Google's index. It seems other people have spotted them too and the story is on Digg.
Here are some queries for which the sites rank really well:
pizza sauce recipe (#10)
profiling racial war (#1)
san jose mission earthquake (#1)
google product manager interview (#4)
grill steak cooking (#3)
Update: Google has removed the sites from the index. Hopefully, they tweaked the algorithms to prevent other similar situations.