Hard to believe, but it was more than four years ago that the Blue Men arrived with their jungles of industrial tubing and turbo-hydraulic water-spouting thingamajigs to test a postpsychedelic generation's affinity for sensory overload. The revue is more clean and collected than it was at its premiere--much of the kinetic clutter has been thinned out to showcase the azure artists' whimsical humor. They amuse with drums that spray fountains of paint, bottle-xylophones in Peter Max colors, costumes that ejaculate mysterious substances, synchronized chewing and spitting, video probes, dancing ropes, word games, and sing-alongs. Then there's the glow-in-the-dark backup band, and the occasional cinematic sequence to give our mute hosts a breather. The show doesn't stop at the edge of the stage--any volunteers to be a human paintbrush?--but the fun is all astonishingly painless, culminating in a communal finale that comes as close to a ticker-tape drowning as anyone could really want. Briar Street Theatre, 3133 N. Halsted, 773-348-4000. Open run: Tuesdays-Thursdays, 8 PM; Fridays, 7 and 10 PM; Saturdays, 4, 7, and 10 PM; Sundays, 3 and 6 PM. $43-$53.