A pretty nifty 3D programming program.
You can make animations, movies and even games.
It is reminiscent of GameMaker due to the drag-and-drop things.

Since I can't explain any better here is their description.
In Alice's interactive interface, students drag and drop graphic tiles to create a program, where the instructions correspond to standard statements in a production oriented programming language, such as Java, C++, and C#. Alice allows students to immediately see how their animation programs run, enabling them to easily understand the relationship between the programming statements and the behavior of objects in their animation. By manipulating the objects in their virtual world, students gain experience with all the programming constructs typically taught in an introductory programming course.

Best of all, it is free but the downside is that you can't import your own 3D models (although there may be a modifyable character base)
I've only just started to use it, and it is great fun.

Here is the site.
http://www.alice.org/index.php

The latest version is 2.2 and version 3 is in the works but will not be released anytime soon. There is a beta however.

There is also another version of Alice called 'Storytelling Alice'. It boasts a larger range of animations but can only make animations/stories.
http://www.alice.org/kelleher/storytelling/index.html

I use this software. It's pretty cool. However people criticize it for things like "I h8 teh dag-n-drop inerface cuz we cant type stuf!"

Does anyone agree with that sentence in quotation marks? Cause I don't.

EDIT: Actually, if you can find a way to convert a 3D model to a .a2c extension, you can import it.

This looks fun to play around with, I'll check it out