what do you want, you want to see Hollywood type stuff, or cool things that show the place has culture, or both?
Go to Hollywood and see Mann's Chinese. It's impressive, the handprints and whatnot.
The Getty Museum is absolutely the coolest place in Los Angeles. Up on a hill, it's a huge museum with a wonderful garden, you see the ocean to the west, then the cityscape to the easy and south. You don't even have to go in and look at the exhibits. Just go to be there. The architecture is spectacular, it's a wonderful place just to spend some time. If you do want to see exhibits, go early, cuz there is no way you're gonna see it all in one day.
UCLA is close to the Getty, could take a walk or a tour there, was built in 1927, started at least, still haven't stopped

. Have to call ahead to take a tour of UCLA, I know they are offered throughout the summer.
Could go to a Dodger Game, Griffith Park, Venice Beach, uhm, another museum, the La Brea Tar Pits. A great museum for kids and adults. There's an area in LA that was tar pits. There were tons of prehistoric fossils in it, as far as I know, they still excavate. Have some hands on stuff, but it's informative and fun, especially if you have any interest in it.
Disneyland is like an hour or so away from LA, depends where you stay. Disney has a new park too, California Adventure. Never been, heard its good though. Knotts Berry Farm is another amusement park that is near Disneyland. Universal Studios is another tourist type place/amusement park.
There's all sorts of places to go. I could think of more, but I think this may be good for now
late.
TDP