Hector Martin's driver will spit out the RGB and IR camera feeds from the sensor to a computer running his code. It isn't that useful at the moment, but could help lead to new uses and applications. The source code can be snagged from his website if you're the hacking type.
The NUI Group, meanwhile, will not be releasing its work until it receives $10,000 in "donations" so this might be your only shot for the time being. And it's free, though Shacknews cannot take responsibility for any Microsoft ninjas dispatched to your residence should they discover your tampering.
A video showing off the quick hack can be found below.