I made couple physics demos using Xith3d and odejava.
You can check try them out at:http://cray.tuug.org/~jani/odejava/
Download the odejava-0.1-full.zip if you want to get the easiest way as it contains jogl, xith3d and other 3rd party libraries and jars that are required for executing the demos. Main directory has three bat files, so click those to execute the demos. Sorry, but odejava currently has only windows binaries compiled, others come later I hope.
On the BoxApp you can change simulations by pressing 1,2 or 3. Keys q,w,e,a,s,d change box sizes (select new simulation after this). Mouse drag with left mouse button adds some spin to boxes and plain left click to bottom or top of the screen gives big force to last object (try it with tower simulation as all boxes are connected to each other, snaky).
On the CarApp you can try to drive around with a,d,w,s keys. b is handbrake (on/off) and keys 1,2,3 change the camera position. Space resets the simulation. Ode's parameters are bit hairy, fix if you want
runOdeHelloWorld.bat runs console based test with couple objects falling to a ground, with no rendered attached to it, so this is a bit dull demo.
Hope people get a spark for developing odejava after seeing these hilarious demos :-)
PS. Use ESC button for exiting from the demos, I didnt bother to catch Xith3d window close event (odejava needs proper cleanup method to be called).
BTW How does one catch Xith3d window close event?