From InkBlog:
The old favorite, Quake2, has been rewritten to run entirely inside the Common Language Runtime. The good folks at Vertigo Software did a great job on the port, even adding a Halo-like radar system to the game. Source code is available too! Go get Quake2.NET now and have some fraggin' fun!
Watch this blog this month for a big announcement regarding Gaming with .NET! (Yes, bigger than Quake2 :-)