NxOgre is a physics connector library between the physics library PhysX and the Ogre 3D rendering system. With a help of some short, fast and neat code you can have a commercial grade physics system powering your Ogre application within a matter of minutes.
See Cake.
You will need the latest Ogre SDK or source release and the latest SDK version of PhysX and of course a C++ compiler.
NxOgre is can be downloaded from the download page, or for who to prefer to compile from source then it is provided via downloading using Subversion hosted at NxOgre.org. The latest Bleeding edge can be downloaded the bleeding edge trunk and the more stable but with less features can be downloade from the 0.9 trunk.
Lots.