Xenia

Current version:	Unknown
Active:	Yes
OS:	Windows, Linux, OS X
Authors:	Ben Vanik
Official website:	http://github.com/benvanik/xenia
Source code:	Unknown

Xenia is an Xbox 360 emulator. However it is very early in development. It does not currently play any games.

Xenia's blog (Very informative blog about where emulators come from).