I stumbled upon some interesting videos that deal with interactivity and video. Check them out.. I think that it's good to get the conversation started now, so that we know what we will be getting into and what is feasible within the time frame that we have to accomplish this. I am not sure of the level of knowledge that this will require or the amount of time spent learning this software, or even more the level of involvement we want with this, but this a glimpse of what is out there.
Some of the programs involved that I have seen are: Quartz Composer (free from Apple), VDMX, and openFrameworks (open source).
This is really cool... this video shows some of the power of projection mapping capabilities of VDMX.
This guy is into some pretty interesting interactive projects. The projects I've seen make use of a lot of motion capture. The results are pretty impressive.
I'm sure we've all seen the head tracking video with the Nintendo Wii... here are a few more of his projects, might be a helpful resource.
Examples of what can be done using Quartz Composer...
This is a tutorial vid that might help understand how Quartz Composer works, and also how it integrates into VDMX.