Sometimes "art in the streets" is actually arts inside an old museum. Which was the case on Saturday evening when the Museum of Natural History threw open its doors to let herds of groovies -- any number of lost tribes among them -- indoors for free. "Art in the Streets" bands played, movies showed, DJs whirled. Werner Herzog was a major presence with Cave of Forgotten Dreams in the North American Hall and then a Q & A with the director himself. There were strange, temporary tents, and video projects in real time. All the while, the somewhat musty (by association if not in fact) dioramas that are the subject of half the museum became a fresh backdrop, as the aging taxidermy had lively company. In one hall, bongos and gazelles, ibex and elephants held their poses as a DJ spun atmospheric dance sets. Dublab from Echo Park lived and breathed and performed in another. A spillover crowd from Herzog's Q & A behaved very well in yet another hall as the director's conversation was projected from next door. They looked like an exhibit themselves.