This is an interesting post - the inventor uses a laser as a point light source for a projector. Essentially, a lens is used to increase the beam divergence. A slide is inserted between the slide and the laser and the result is a large, sharp image projected. It is monochrome but neat…

The device has a pretty small parts list. A good summary can be found here:

http://www.gadgetvenue.com/custom-laser-projector-12221458/

and here: http://hackedgadgets.com/2007/12/22/laser-image-projector/

And the original Instructables post can be found here:

http://www.instructables.com/id/Laser-Image-Projector/