Omnivorous Surfer

SlapStick dry-erase replacement boards are installed on top of existing chalk boards or even on walls. This would be much cheaper than buying dry-erase boards. The company also has SlapTape, a double-sided tape for hanging posters which, they say, should not remove paint on most walls. The website has a link to a YouTube video which demonstrates the ease of installation (video recorded using a Flip video camera, but that's another story).

I think the tape could be useful in the home, but the replacement boards and tape would definitely be useful in the classroom at any level.