If you want a lazy beach where you can just lie on your back and ride the swells Redondo Beach is great, plus I love stuffing myself with oysters at the seafood market on the pier there. If you want a beach with big waves that are fun to bodysurf then it's Huntington Beach any time there is a storm in Baja since it's south facing. Zuma Beach around Malibu is nice too and has good waves, and you'll surely recognize it from a billion different commercials. Mt San Jacinto out towards Palm Springs is a great hike on a clear day as it's like 10800 feet and you look out at the Coachella Valley that's like 500 feet, so it's a really prominent peak. Plus you can ride the aerial tram up to around 8200 feet making it a not too tough dayhike. Angeles Crest Highway to around the Mt Wilson area was always my favorite drive in the area when I lived there, though they had an enormous forest fire along it like a year after I moved out of the area and I haven't been on it since so don't know how scarred the area is now. Also highly recommend taking a day trip to San Diego to check out the Air & Space Museum with a big A-12 in front (a single seat predecessor to the SR-71 Blackbird) and tour the aircraft carrier they have open to the public. Thought it was even better than the Smithsonian Air & Space Museum in DC. If you're into old west stuff Vasquez Rocks along the 14 north of town is kind of cool since so many things were filmed there (including my favorite De La Soul video, RIP Trugoy). Another nice day trip is to take the car down the 5 to San Ysidro, park, and cross the border into TJ for the donkey show and to take a picture with the zebra. Don't drive into TJ though, the cops will rob you blind.