World Builder from Bruce Branit on Vimeo.

It reminds me of an idea I was talking over with some of my colleagues from the Shanghai Student Film Festival about teaching a video class entirely in Second Life. The students would spend the first part of the course learning about 3D design. They could build and design props, sets, costumes, and characters. Perhaps develop a second life movie studio and set. In 'first life' they could learn the basics of film-making; the cinematography, lighting, editing, and sound. Then in the second half of their course they could combine those skills towards the creation of more complex machinima videos.

Speaking of which, check out this amazing community project from Urangan High School in Australia. They've raised over 50K for a two year project exploring 3D animation and video. You can follow their production blog to see what they've done and where they are going.

Finally, I haven't tried it out for myself yet (I haven't touched Blender in a few years now unfortunately) but it looks like Juan Pablo Bouza has developed a free character rigging system to help make quick human figures for your productions.