Hey, just a quick link I found on Wikipedia :
Maybe you already heard about Atlas, Monad, Origami, Avalon, InfoCard or Kahuna... but did you know Springfield (Popfly) ? Sparkle (Blend) or Q (Windows Home Server) ?? Or maybe you don't care ;-) if not, you'll find the whole list of Microsoft Codenames there. While always on the cutting edge of technologies, working most of the time with codenames and beta products, this can be useful when a bit lost among all these names.