Pirelli reports 147 overtaking moves during the Brazil GP - new record! On the F1 technical forum, there's a great overtaking statistic thread for the 2012 season. (I don't know if they'd like us to simply copy their posts, thus just the link.)
No surprise there. Vettel alone probably got close to the record . By lap 8, it almost seemed like there had been a full race already. It was great. That's what rain does for you .