At 86 x 44 x 85 mm, the Oculon Hikari Pro is the world's smallest projector. It comes in Pro1440 ($399) or Pro920 ($299) models, with the former boasting "250 lumens across a 20-inch, 800 x 600 pixel display from Composite or D-Sub15 RGB connected sources." Click here for first picture in gallery.
On the lookout for portable projection? The pair can project a 15- or 20-inch display from a distance of just 2-feet[via Engadget]