Also, I should make clear that I'm doing this personally; the fact that I work for Google has nothing to do with it. If anything, I think Microsoft deserves props for bringing such cool technology to market. I hope Microsoft does really well with the Kinect and sells tons of them.
I do hope that the Kinect cost of materials is low enough that MSFT doesn't lose money on each Kinect they sell. But I have to think that the tinkerer/maker community is much smaller than the mass market for video gamers. My guess is that Kinect purchases for Linux will be a barely blip on MSFT's radar.
The Kinect experience so far is targeted at a wider audience than the traditional gamer. My mother, for example, absolutely loves the Kinect. She particularly likes the Tai Chi and yoga trainers in the "Your Shape" game. I didn't expect it to take off with her the way it did, but it's the first video game system where she really wants to play it.
Another thing: there are several different interfaces embodied in the launch titles around the same basic Kinect capabilities and interactions. If you want to develop new user experiences, now is a good time to check out what people are doing before everything settles into place. So it's worth at least visiting a friend who has one.
(Disclosure: I work at Microsoft. Speaking only for myself here, of course.)
But a person/team making it easy to write programs that use the Kinect on Linux may not be able to sell the software. So a contest makes sense.
On a side note, I think that the vocal capabilities of the device are far over looked. The voice recog is amazing.