'Snowshow' excels at the sort of giddy physical humor that tickles belly laughter from children. A clown with a torso pierced by arrows dies extravagantly, and bloodlessly; the clown culprit, bow in hand, is darling anyway. But this piece isn't only for kids, and it's not all frivolity. There's a forlornness to some of these clowns, and a loneliness. Sometimes they're scared, too, though they give us no cause to be.