Here is some of my stuff currently using the Newton physics engine.
Tractor Beam
Tower Cannons v0.1 (745kB) Water Window v0.1 (112kB) Marble Labyrinth v0.2.2 (12 March '05) (1MB) Marble Labyrinth source Code v0.2.2 (12 March '05) (1MB) Tutorial 1 (372kB) Tutorial 2 (428kB) ODE Tutorial 2 (76kB) A main difference was that I was not able to get dynamic timeslicing on ODE working well so it uses a fixed timeslice. My first impressions are that for this example the ODE code is slower; however ODE does need a lot more tweaking. For example, Newton automatically sleeps bodies, and I haven't switched sleeping on for ODE. Finally after a while of running ODE crashes for me. 
A 2D space arcade game using Newton physics.
Shoot each other off towers of blocks. With source code.
Splash water around and over your windows. Create new windows and design your own waterfalls. Avoid work. — With source code.
Roll around a maze. Now has tilting motion and sound as well as support for the AMS.
For your enlightenment.
A Cocoa version of the first Newton tutorial.
A Cocoa version of the second Newton tutorial.
An ODE version of the second Newton tutorial. With these you can compare the two physics SDKs performance. — These two tutorials are mostly the same, and neither of these has been tuned or tweaked for the respective physics engine.