I've used chalk board paint. It really doesn't work, and you can wash it down w/ a wet towel w/ out leaving any marks. Although, I really think it's nothing more than flat black paint.
Not very expensive ($13 for a quart maybe?).
I wanted to do magnetic paint, but at $80/gallon, I figured they can draw on the walls and I can hang up a piece of metal for magnets.
But it does work. And clean up is easy as it's latex based.

did you mean to say it doesnt work or it does? :) kinda got confused... thanks!

Oh... sorry. It Does work. Total typo.
I'm very happy w/ the finish of it and how nice it cleans up when you draw on it. I did 2 coats. 3 probably would have produced an even better finish.