A small bluetooth connected, wall-mounted projector that display the calendar from your computer on the wall.

So I'm thinking that instead of having a big dry erase calendar on the wall of the office, you have a little wall-mounted box that projects the image of your calendar from the information on the computer. It would also allow you to use the included stylus for adding/removing appointments synced to the computer through the wall projection. You could also change views from daily to year at a glance styles.

edit: An interesting way of doing this would be to use a short throw projector and then integrated with something similar to the laser projection keyboard. Perhaps something like a kinect that can track your x,y coordinates on the wall with a pressure sensitive stylus that will activate when you write something.

Or there are actually projectors with interactive stylus built in, from Epson... so my idea is already done. ha!