Place rocks/stones over campfire to get hot. Then put them on picnic table and have kids color them with crayons. The crayons melt onto the stone making it look like paint! We did this on our girl scout camp outs. Fun things to do on picnic table.
Summer Activity Idea List - indoor and outdoor activities. I realize this is probably meant for little kids, but all of these things sound fun! Doesn't have to do with next year but will be good for this summer!