The young Obama popularized the concept of 'roof hits', when all the windows of a car were rolled up so you could suck up the last bit of smoke from the ceiling. 'Wasting good bud smoke was not tolerated,' Tom Topolinski, one member of the Choom Gang, told Maraniss. 'Barry also had a knack for interceptions. When a joint was making the rounds, he often elbowed his way in, out of turn, shouted "Intercepted!", and took an extra hit. No one seemed to mind.'