A must-stop while in Southern California is the Getty Museum. The modern architecture of the building itself is reason enough, but they have wonderful collections there as well.
I have been there several times, but for some reason I never took the architectural tour. It is daily through March 26th at 10:15am, 11am, 1pm, 2pm and 3pm.
It was very interesting and only takes 45 minutes. Richard Meier (post to follow on him alone…) was the genius behind this building.
While you are at it, take a tour of the gardens as well.