Absolutely. You can get a PrimeSense or Kinect camera if you are a serious game developer. You can also just purchase a Panasonic D-Imager depth camera for a few grand. Probably there will be a dozen of these cameras at consumer price points within a year or two. Having the data from the cameras, as pointed out, is somewhat limited.
Creating algorithms that will analyze movement takes about 4 years, and you can get this software from Softkinetic and from Omek (I work for Omek). Microsoft has obviously developed its own software, but it probably won't share it with you. Omek also has a gesture recording capability, which means that instead of programming new moves, you can actually stand in front of the camera and record new moves. You need to use a number of different people to get it right, but it does reduce development time dramatically. So anyone serious about this doesn't have to re-create this --it's out there and you can license it. Eventually there may be open source solutions, but it will take a while.