A Blender 2.6+ addon that aims to implement Motion Graphs
...The add-on can import set of motion captured BVH files and construct a motion graph based on some given parameters. This motion graph can be stored in memory and used until Blender is running, or can be baked to a file in a compact format so that it can be retrieved later without the need of re-computation. This motion graph can be used to generate arbitrary length motions that is composed of frames from the original motions and some generated transition frames between them.
The add-on is currently being extended for path synthesis where the the animation required to make the character traverse an arbitrary path will be generated from the motion graph.