C.G.
well if the sides are exposed you can use the sides, if not I bought the chalkboard/magnetic board from Pottery Barn Kids, they hav eit in small or large. It is both a chalkboard & a magnetic board, my kids love it.
http://www.potterybarnkids.com/products/md9300/index.cfm?...
Also at any hardware or home improvement store they sell magnetic paint. You can paint a square and out some kind of border around it. Good luck!!