The California Supreme Court, California's highest state court, is located only a block away from the Hastings campus. The Justices hear cases in San Francisco several times a year, generally in March, May, and September. Other months the Court hears argument in Los Angeles or Sacramento, and occasionally on a one-time basis at other locations.
The Court provides us with detailed information about its San Francisco sessions. Its overall oral argument calendar (without detail about the cases) is organized by month in a PDF format.
The Court maintains on its website information about some of its high profile cases. Included is audio/video footage of the Prop 8 oral arguments.
If you wish to bring a group contact the Office of the Clerk in advance, as courtroom space is limited.