My Game Engine's code for XNA now on Codeplex
C# Engine code for XNA platform.
from 
Stardock Forums
Stardock Forums
I uploaded my game engine code to codeplex to personal use. However, it is available for anybody to use for free. It is a 40K engine, written in C# for XBOX-360 and PC development.
I am currently using it to create my Indie game PumpkinToss and TemporalWars at XNA website.
temporalwarsindieeng.codeplex.com.
Ben
www.temporalwars.com