The Rolling Stones turn 50 today. In 1962, Mick and Keith were just 18, and Mick was still a student at the London School of Economics. Then known as the Rollin’ Stones, they played at London’s Marquee, a basement club, to a crowd of around 100. Today, well, they are the kings of rock. The Stones are planning something big to mark the occasion (their site has been coyly alluding to it), while The Rolling Stones: 50 book and photo exhibit at London’s Somerset House debut Friday. Rock on, Stones.