I have created a small physics test map for use in Counter-Strike: Source. It contains a see-saw, falling barrels, dominoes and a breakable computer, and is made to complement the
Source physics tutorial. I will also put up some beginners tutorials next week when the full game comes out- there are a few too many bugs and un-implemented features right now to be able to write one safely!
Download it from here. (116kb)
Update: I am an idiot and put the wrong VMF inside! Download it again and there will be a map you can edit showing all these features inside.