[youtube http://youtu.be/NMbnvr4y488] KinectToPin UI Panel 1.2 is a major update and should make rigging and animating your mocap characters in After Effects much more intuitive. Download it here. Copy both the jsx and ffx files into your ScriptUI Panels folder. Requires CS4+. New features: New skeleton visualizer! Easier 3D manipulation....

The birds in this clip were animated in After Effects, but their flocking motion was generated in Processing.

All you need is a webcam.