CL-Sokoban
CL-Sokoban implements the classic game Sokoban. It has a dumb, unplayable UI that will work on any implementation, a simple terminal UI that ECL compiles to an executable, and an Emacs UI, using SLIME, that runs nicely off of SBCL. More are wanted.

Think of it as an exercise in showing how a 'common' codebase can take easy advantage of the special abilities of the various implementations.

Also, Sokoban is a pretty fun game :-)

Get it from Github.

Game