If you want some racing action to keep you busy until the new Trackmania is released, then you might want to take a look at Stunt Car Online. It is a racing game with some light weight physics and a wacky track designs built on the Unity engine.There is apparently a downloadable version of the demo, but the link on the blog doesn’t want to work for me which is very frustrating. Regardless, you can play the online demo here to get a feel for things. You can also find some videos and more images on the ModDB page.