Last night I took the time to visit the Norton Simon museum in Pasadena. It's something I've been meaning to do for years. I highly recommend it. They have a split collection. One half of the museum is Renaissance and earlier (including a lot of Indian art), the other is 19th century and beyond. Although there are some great works in the Renaissance collection, I prefer the contemporary works. There are three Van Gogh paintings, any one of which alone would make the visit worthwhile.
The museum is free the first Friday night of every month. It was not crowded last night. It's not a huge museum, so you can do a good walk-through in about two hours.