Jonathan de Halleux started an open-source site called NCollection, where people can contribute the collection classes that are missing from .NET (trees, sets, linked lists, ternary search trees, circular buffers, etc.) and put them all in one namespace. They'll be emphasizing coding standards and peer review, unit testing (using MbUnit), and FxCop. Very, very cool. If I get some time off from packing, I need to check them out; maybe I could contribute a HistoryList/UndoList.