Seashell paint makeover: spray paint inside of shells high gloss baby blue and paint outside with gold or silver paint. Maybe could do this with something else from nature if your home isn't beach themed.
Bonhommes de neige et empreintes de doigts Fingerprint snowman. This would be so much fun if they made all the snowmen themselves but had everyone in class make the parts. So, if there are 25 kids, they make 25 snowmen and each kid makes one.
During these past few hot evenings I have been hard at work making a pair of driftwood and sea shell mirrors. The driftwood was found on a beach in West Wales - lovingly selected and pieced together, along with some lovely sea shells and star fish.