Multitouch Without Touch Using Wiimote
owlgorithm writes to mention that Gizmodo has a neat hack for the multitouch Holy Grail — multitouch without the touch. This hack turns the Wiimote into a receiver for IR light reflected from an emitter off of your fingers using reflective tape.
I would be careful making very bright infrared light. Because your eyes do not pick them up, your pupils will not know to shrink in bright infrared light.
I would suggest doing this in a very well lit room, and NEVER in the dark, or you will likely seriously damage your eyes.