My solutions to Project Euler problems in Haskell.
Whilst some might argue that giving away solutions to the Project Euler problems isn't on, all the solutions can already be found at http://code.google.com/p/projecteuler-solutions/wiki/ProjectEulerSolutions, and Haskell code for the first 200 can be found at http://www.haskell.org/haskellwiki/Euler_problems...
Personally I like having solutions available online - it allows me to check other people's answers after I've done my own to see if I could've done something better.