As noted in some other thread, James Hetfield of Metallica's kids went to my kids' school -- got to meet him several times. His seats at Oakland Raiders NFL games were also the row in front of my lawyer's so I met him there too.
Grant Imahara from the TV show Mythbusters used to date my brother's ex-wife's cousin (they were on the same nerdy fighting robot team previously). Seems tenuous, but he and her and me and my wife went out to dinner three or four times just as he began to get famous here in the States. Really, really nice fellow -- and very smart.
I went to college with Nancy Pelosi's daughter (she dated a friend of mine -- she was WILD in college), worked at the same company as Nancy's son (but didn't know him well), and her nephew is a very good friend still. The Pelosis are kind of everywhere in San Francisco.
I played a round of golf with Fluff Cowan -- Tiger Woods' first caddie -- when he was still caddying for Peter Jacobsen. Fluff was a stick (a +2 index/handicap). He broke out a joint in the middle of the round and offered me a puff. I don't usually do that stuff (since college anyway), but couldn't pass up the chance. Afterwards, we hung out in the clubhouse with Huey Lewis.