A 3d modeller/renderer made by a Dutch company called "Not a number". It's totally free, but supports a lot of features from commercial packages, including nurbs and a very good render engine. From the same company you can also get gameblender, a version for games.

The interface looks very non-intuitive(sp?) at first, and some people claim it really is. But if you continue, and slam yourself through your anger and some tutorials, it starts to more userfriendly. And after playing with it for a while, you don't want anything else.

The interface is one of the most functional and intuitive user interfaces ever made. It becomes one with you.

www.blender.nl(english)