If you want to spring for a day at a theme park, there are a few attractions in LA as well as outside the county.
Universal Studios Hollywood, an operating film studio-cum-theme park in Universal City, has a range of draws from thrill rides (Transformers: The Ride 3-D is new) to the studio tour (including the Peter Jackson-directed King Kong 360 3-D) and adjacent Universal CityWalk, an admission-free shopping and entertainment center. The brand-spanking-new Lex Luthor: Drop of Doom—the world’s tallest vertical-drop thrill ride—is the ride of the moment at Six Flags Magic Mountain in Valencia. The tiny Pacific Park at the Santa Monica Pier is a park that presents less of a time commitment, with a few rides including a solar-powered Ferris wheel and the West Coaster, food stands and midway games.
Trek to adjacent Orange County for the happiest place(s) on earth, or at least in Anaheim: Disneyland and Disney California Adventure Park, whose latest attractions are the newly upgraded Matterhorn and Cars Land, respectively. The newest thrill ride at Knott’s Berry Farm (8039 Beach Blvd., Buena Park, 714.220.5200) is the Windseeker.