If you would like to have an interactive whiteboard in your classroom, but your school can't afford one of the commercial offerings (those things are wicked expensive) don't despair because there is a very affordable alternative. Nintendo's Wii remote can be used to create an interactive whiteboard. The first time I saw a Wiimote Whiteboard was in a TED Talk given by Johnny Lee. The videos and links below will provide you with what you need to know to build your own Wiimote Interactive Whiteboard.
Here's Johnny Lee introducing the Wiimote Whiteboard at TED.
Here's Johnny Lee showing you how to assemble the needed parts.
To get more directions and to download the free software from Johnny Lee, visit his website.
All Together We Can Learn has a twenty page PDF about building and using the Wiimote Whiteboard.