Ask any developer, having a utility library available when building applications can save a you a lot of troubles. As part of a project to create gestural based character movements in second life (Armadillo); John McCaffery has developed NuiLib, a library which works with the Kinect in order to alleviate much of the heavy lifting and provide a means to ease integration of NUI devices into applications.

I really dig the end result of this hack. Using Quartz Composer and TUIO, this project dubbed "Stretchy Lines" has came to life thanks to that handy depth sensing wonder toy Kinect. The setup includes a Kinect perpendicular to the table. The TUIO Server detects objects within a specific range, and then a calibrated projector draws random lines around the objects detected.

TUIO sends objects coords using OSC protocol to Quartz Composer, and then the graphic is rendered using custom Quartz Composer patches.

Looking to amp up your bath time excitement? Yeah, me neither, but maybe couples who like to drop acid durring bath time would get a kick out of this one. All you need is a projector mounted above your bathtub (yeah, that's safe) and a little OFX know-how and you too can turn your bath time bubbles into psychedelic masterpieces.

Jomario Murta submitted a great writeup pertaining to his markerless, point cloud generated reference method for producing animations and MoCap. Here's what he had to say about it:

As you probably know, already exists some motion capture softwares using the kinect on windows, they are quite interesting once the capture is made without needing marks, and it can be exported to many compatible formats, like the BVH and the FBX.