Jamie "NUnitAddin" Cansdale (fellow UK .NET blogger) has set up Code Blog, where you can interactively "solve" a coding challenge by fleshing out a stub implementation until the provided unit tests succeed (very XP ;). Apparently he's in the market for some more challenges (i.e. a stub plus required unit tests). Now if we could just get "Prag" Dave to submit some of his code kata...