Aliens is a game that was created by the MS in Game Design & Development crew, as well as a few rockstar undergraduates. It was developed simultaneously in C++/DirectX and C# XNA (both PC and XBOX 360 versions). You can download and install the XNA versions here:
Windows | Xbox 360
Note: These require XNA Game Studio Express 1.0 Refresh (and a Creator's Club account for the Xbox version).

This game was used as a demo of RIT's programs at the Microsoft GameFest 2007 Keynote given by Chris Satchell, GM of Microsoft Game Development Group / XNA. What more needs to be said? You can abduct cows, terrorize the populace, and destroy everything you see... all while fulfilling the missions of your alien overlords and avoiding detection of the radar systems. Download and play today!

Check out a video of Aliens in action below, and another by clicking the "Read More" link: