Old West
My first thoughts for your BB are about roping. Cover BB surface with bandanas. Trim your BB with rope (bailing rope, sisal, whatever). Fashion a lasso and "wrangle" some of your favorite book titles on the BB. Include a construction paper split-rail fence. Maybe you could also hang a cardboard wagon wheel, then use inside sections of the wagon wheel on your BB to earn class or individual incentives: "fill up all the sections and you'll get ___."