Well did you check out that ODE physics engine linked to above?
Yes, a long time ago. It's yet another particle/spring system.
Some of them bounce really high and stuff but I have to assume that's the fault of whoever made the demo.
No, that's because the underlying physics system isn't very good.
Hitman is a silly little game with bad physics?
Can you provide an URL or something? I haven't heard of Hitman.
Try to stack up objects using ODE...
They bounce all over the place, even from a standstill. That's because spring physics are inadequate for most realistic applications. You can't get friction or surface forces to work with particles and springs!
PS - the ODE's dll locks up and throws errors all the time too. I wouldn't recommend using it at all. :(