UPDATE: Bikers leave one man unconscious after mob-style beating.
Cambridge Police report two guys, apparently fed up with a motorist who "swerved into and encroached upon" the Mass. Ave. bike lane around 11 p.m. on Saturday, caught up with the car, dragged the two people out and began beating them - one into unconsciousness - in front of 250 Mass. Ave.. Both alleged perps arrested.