From the Vimeo page:
A fully functional Super 8 Movie Projector I built using Lego Technic. The only non-Lego parts are the lens, the reel spindles and the lamp.
The projector uses just two engines and is fully featured with automatic feeding, 24 fps, fast rewind and 120m reel capabilities. A decent LED flashlight makes it pretty amazingly bright. :)
Video after the break!