   C# physics engines for mono?
  So far I've found several physics engines for C#(I'm looking for 2D physics), but they all say that they were designed to be used with XNA(BulletX, Farseer).   
  Check out Physics2D.net.  I don't know for a fact that it works under mono, but from what I remember it doesn't do anything magical that mono wouldn't be able to handle.   