If you can't get the other kids to make squares (using good old fabric markers), have your own child do one. Or trace your son's hand, transfer that to fabric and machine applique them to simple blocks, add bindings and viola. Or if your state has a star pattern block (like we have Ohio Star), or. . or.. or.. I was thinking about doing a wall hanging for my kids' teachers this year too, but I don't think I can dig my way to the sewing machine just yet. . .
You'll get lots of great ideas here!