There's always tons of stuff going on in LA. Are you looking for fun stuff in general? Food? Driving?
For car stuff, checkout Cars and Coffee in Irvine on Saturday mornings.
For other up and coming local events, start checking out some local websites with whats going on closer to your trip:
http://laist.com/
http://www.reddit.com/r/LosAngeles
http://www.reddit.com/r/orangecounty