Oil Drip Pan Chalkboards! Spray prime the drip pans with gray primer, and then use latex chalkboard paint. Tape a border around the edge of the drip pan so it will create a 'frame' of sorts. Hang the boards/pans using 3M Command Strips (4 medium sized ones did the trick).
"And no playroom is complete without a magnetic board... All you need is a $10 oil drip pan, usually found in the automotive section at Walmart. Since it's not very pretty on it's own, a coat of spray paint dresses it up nicely."