We reported on the Carnegie Mellon University's motion capture library before. Back then you needed to manually convert the files to the .bvh file format to import them into Blender. Jennifer Sumbu Longe has republished the entire collection and did the conversion for you.
Jennifer Sumbu Longe wrote:
I am the owner/admin/webmaster of THE TRAILERS' PARK and I just wanted to give you some news which I think your readers might be interested in: I have converted the Carnegie Mellon University Library (2548) and Kitchen Motion (5) in six formats: bvh, dae, fbx, mb, max and vns (iCLone); and Mocap Club Files (500) in five formats bvh, dae, fbx, mb and max. I believe Blender can read bvh, dae and fbx.
I hope that the community will be pleased.
The data isn't organised too well so you'll have to do some downloading to find what you need.