Running Clean

Like a cow catcher on a locomotive, Bay to Breakers clears the stupid from the streets a few months before the San Francisco Marathon roars through town. Still, you might be fondly eyeing your Papa Smurf costume there in the closet, so consider this: Today's 26-mile race, which crosses the Golden Gate and winds through the Presidio, is tempered by two half-marathons and a 5K, which runs along the breezy Embarcadero. And a post-race barbecue features no running at all.