I moved this thread to the Southern California forum, as it's more about SoCal activities than it is about Disneyland planning...
I agree with sheetz. A stop at the Original Farmers Market on Third and Fairfax -- which is right next door to The Grove, a place where TMZ hangs out undercover, waiting for celebrities -- is worthwhile. The array of food there -- some of it can be found at newer establishments, and some of it can be found at longtime family-run counter service places -- is amazing. It's a historical site in Los Angeles, and it's one of the city's true treasures (touristy or otherwise)!
Plus, according to something that was on the Farmers Market Facebook page last year, "...when Walt Disney worked on early designs for Disneyland, he did some of his work while dining on Farmers Market patios."
The Tar Pits are just a few minutes south of Farmers Market, and they are next to the Los Angeles County Museum of Art (which has already been mentioned in the thread).
At the front of LACMA (Wilshire Blvd. side) you will find the wacky street lamp installation, as well as the free sculpture garden. At the back of LACMA (6th Street side), you will find Levitated Mass -- which is an art installation that is a gigantic boulder (you can walk underneath the boulder, and the forced perspective is kind of interesting)!
There is also a restaurant that is part of the Patina Group located at LACMA (Patina is the same company that operates Catal, Uva Bar, Naples and Tortilla Jo's in Downtown Disney at Disneyland Resort).
Going along with the "Disney theme", if you did visit LACMA, you'd be near another interesting area.
Although the actual theater isn't there anymore, you're just a few blocks away from "Carthay Circle". (This is the theater that premiered Snow White & inspired the building & restaurant at DCA)
At this point, the place where the theater was is just office buildings, but there is a large stone sign on San Vicente that says Carthay Circle.
That's all there is & obviously, this isn't anything to go out of your way for, but if you're at LACMA, it might be cool to take five minutes & drive by it.