According to TV viewer Maurice Degroot, every phase of rock band The Who's career was traced by a single CBS commercial break Tuesday. 'The retrospective opened with Hummer's 'Happy Jack,' one of the songs from The Who's '60s mod period,'Degroot said. 'Then a Saab commercial played 'I'm Free' from their ambitious rock-opera phase, followed by a promo for CSI featuring 'Who Are You,' one of their last great hits.' In light of the popular commercials, the surviving Who members are planning a reunion tour to perform 30-second snippets from all their famous songs. 