Hi. For my Netflix Prize project I have implemented two reusable modules. The first module implements a random shuffle on immutable lists. It uses http://okmij.org/ftp/Haskell/perfect-shuffle.txt, with an additional "wrapper" function, having a more friendly interface. The second module implements a function used to partition a list into n sublists of random length. I have pasted the modules here: http://hpaste.org/fastcgi/hpaste.fcgi/view?id=2483 http://hpaste.org/fastcgi/hpaste.fcgi/view?id=2485 If someone is interested (and if Oleg give me permission), I can release them as a package on Hackage. I need to improve documentation, however. In future I can add an implementation of the random shuffle algorithm on mutable arrays in the ST monad. Manlio