clever tote-boxes from Family Fun. As with everything I put on here, it was over-the-top easy. Just cut the flaps off, I tore them off. And cut out some handles...I used a box cutter. The one at Family Fun was modge-podged all over for a more decorative look. I just glued a piece of paper that each kid decorated themselves to the front.
Supplies--minimal, on hand
Mess factor--few scraps of cardboard
Fun factor--too fast to be fun, but we got a lot of compliments on them at the park
Sidenotes/learned by experience--cut the handles at least 2 or 3 inches down from the top, and don't make them too wide, otherwise they tear out easily.