Located off the Pacific Coast highway, the Getty Villa makes for a beautiful and educational day trip.  The Villa itself was modeled on a villa from Heculaneum, a city destroyed by the eruption of Vesuvius in AD 79.  Many of the details, however, are taken from other villas in Herculaneum and Pompeii.  The Villa boasts incredible architectural details and historically accurate gardens that are worth a visit on their own, but if that doesn't entice you, it also hosts a variety of changing exhibits dealing with subjects from ancient art themes to modern conservation techniques.  Take one of the free guided tours and be prepared to have your brain stuffed full of interesting facts.   The cafe, while a little pricey,  has good food and a terrace with a beautiful view of the villa and the ocean beyond. 

Parking is limited, so the Villa requires reservations unless you arrive by public transit.  Admission is free, parking is $10.