From SFWiki

The Cable Car Rally is an annual event usually occuring on the Monday before the Big Game between Cal and Stanford.

Spirit groups from both Cal and Stanford participate in a multi-site San Francisco rally, with most of the action taking place on cable cars. Typically, the starting point is at the cable car turnaround on Powell Street.

Other than cheering and songs from both marching bands on the cable cars, rallies will typically occur in Pier 39, Ghiradelli Square, and Justin Herman Plaza.