GolfScript
flagitious (sometimes to be found in #codegolf on irc.freende.net) has released GolfScript, in his words:
GolfScript is a stack oriented esoteric programming language aimed at solving problems (holes) in as few keystrokes as possible. It also aims to be simple and easy to write.
This is pretty impressive. According to Carl it can solve the codegolf grid-computing challenge in 21 bytes. The next best effort would ba a Perl solution in 43 bytes. It hasn’t been implemented as an allowed language yet though, maybe in codegolf V2.