Another free place to go that is fun and interesting is the old la zoo. the cages are still there and you can walk into some of them. if anything it is a fun place to take pictures and it is a great hike. It used to be where you can walk inside more of the cages and see some of the interesting graffit that is in there, but they have blocked it off for reasons I am sure are good. There is also some free shows going on there now on the lawn. It makes for a really fun afternoon of exploring and picture taking. It is located around Shanes inspiration. If you go on the same area as Shanes inspiration, but drive back a bit, or walk past the restrooms, you go up the hill and there it is. There is also a great big grassy area to play ball and have a picnic and usually not too crowded.
(Here's a map to it.)
Check it out!