Hitachi's StarBoard combines your computer with a chalkboard in a seamless fashion. Controlled by an IR pen, the Starboard allows you to edit Excel spreadsheets, easily map diagrams or, as Jesus is doing here, draw Batman.
The StarBoard can integrate with any computer and projector, though Hitachi recommends their vertical projection model. Nicest bonus? You can record AV and play it back later. The StarBoard was just announced here at IFA and will run 4,600 euros. But damn does it look good—and super easy to use.