[rog8811] sent in this really cool hack where he used the optics sled from a PS3 as a foundation for a 7 color hand held laser projector. Combining a green laser, a blue ray laser, and a red laser, he is able to produce a variety of color  including white. There are step by step instructions on how to make a multicolored laser. He then goes even further, showing how to integrate this into a hand held projector with pre programmed patterns. You can see some examples of the different colors and patterns in this video.