My solutions to the 99 Haskell Problems.
The file are structured according to the subpages on the Haskell wiki, all randomness (e.g. 21-28 followed by 31-41) comes from that.
I usually come up with my own solution, then compare it to the ones in the wiki. If I see anything I like, I make sure I understand how it works and then incorporate it into my own solution.