1 Build software that recognizes blobs.
2 Build software that projects a video composition which responds to the user's blobs.[Hardware]
3 Build the sink with the IR lights (Many thanks to Ikbal for them!)
4 Modify the PS3 Eye camera to read only IR light.
5 Add the semi-transparent projection foil and the projector.
6 Calibrate so the projection fits the user's input.
I'm currently at number 2. If it wasn't for a Quicktime Update (?!) I would probably be much further than that.
Now, firstly I'll try to make a simple functional software so I can go on with the construction and when I am done with it I'll return to enhance the projection software.