The most basic sense of fun improvises on chance gifts of the environment. Snow-fun is too immediate to need rules, either. One game suggests another. First a chaotic battle sequence, with snowballers spied on from behind tree trunks, a little hill to be conquered; then everyone unites to slide down a bigger slope, in squealing collective release. Finally, a massive snowball that is implored to roll downhill. Snow, so protean and malleable, so resistant in bulk; so soon to vanish.