Somebody's writing a clean-room implementation of Solomon's Key for the NES. All of the original levels are already implemented. Theoretically cross-platform. Doesn't quite work yet but it's getting there. Includes a level editor so you can build your own levels. Seems to have some tricks to getting it to run but I haven't tried them yet.
An open source clone of the game Worms in which you manipulate a team of characters (usually earthworms) to box, pummel, blow up, and otherwise mangle the characters of the other team in a cartoon-like fashion. Network/deathmatch play possible.