Ask HN: Best place(s) to find datasets to practice ML and DM?

[schtog]

Anyone know of good websites with collections of datasets that are good for practicing datamining and machine learning?

The netflix prize, www.netflixprize.com is one obvious one, but only 1 set.

Project Gutenberg is another where you can get large amounts of text. http://www.gutenberg.org/wiki/Main_Page

Datasets for medicin would be greatly appreciated.

[kobs]

http://www.cs.utexas.edu/users/sherstov/pdmc/

[ryanwaggoner]

Would freebase work for what you need?