Celebrities, nice. I'll tell you a celebrity sighting story (not in Irvine though). Eight years in LA certainly had it's disadvantages, but occasionally, I got to see famous people. So, one Friday night, I'm at the Trader Joe's at 3rd and La Brea and I see Ashlee Simpson with one of her dumb friends that she lived with at the time. Now this was, mind you, just after she had gotten busted for lip-synching on SNL. It took everything I had not to go up to her and start moving my lips without saying anything.
Other story: in the car on the way to House of Blues once, some guy was wrecklessly jay-walking and we nearly hit him. It was Emilio Estevez, coach of the Mighty Ducks!
(Question, what does homeless guy look like? I once snapped a picture of the only homeless guy I've ever seen in Irvine.)