Most late afternoons when there's a decent breeze, you'll find lots happening at the San Diego Glider Port off of Torrey Pines Road near the University of California San Diego.  Head down the lane to the parking lot.  The vista itself is breathtaking, as you're situated high on a cliff with a spectacular view of the beach below and miles of coastline in both directions.  On a clear day, you can see all the way to the hills of Mexico. 

From atop the cliff, you'll see a parade of surfers in wetsuits, hauling their boards up and down the perilous path up and down the cliff to the surf below.  Below you you'll see them paddling out, waiting to catch a wave, or riding a wave in to shore.

From the parking lot, look to your right and see who's gearing up for a launch.  Somebody's always putting his glider together or taking it apart, testing the wind or chatting with the other gliders about where the currents are.  The launch itself is dramatic, as the glider simply runs full-speed off the cliff.  Above you can see as many as 15 or 20 gliders soaring up and down the coast.   Visit the Glider Port during a major tournament at Torrey Pines Golf Course, and you'll find the air traffic at its peak. Occasionally a glider sets himself down on a green during a tournament, much to the chagrin of the pros.

Finally, if you're daring, inquire at the glider base about taking a tandem flight.  It's terrifying and exhilarating.