I've been going since 2008. I won't be going this year because I'm saving up to go to Hong Kong for the Lantern Festival.
When I went last year, I basically decided to just go with the flow and sorta let things happen rather than go in with any sort of set schedule of "i'm going to hit this panel at this time." So, I was walking toward the convention center and I walked up to the Top Gear display they had on the sidewalk. Got a nifty lens cleaning cloth from them after filling out some form for a competition they were having that weekend. Didn't think anything of it afterwards, until I got a call from the Top Gear Producer the next morning telling me that I had won the contest and me and one other person could go to this party that Top Gear was hosting in one of the hotels near the convention center. My buddy and I went to the hotel and got to shake hands with Kate Beckinsale, she's tiny by the way. We go to the party, have a good time. When we leave the party towards the evening, we run into Fricking Mark Hamill!!
Now I've made it a point not to get star struck at these things, I mean these are human beings just like you and me. They all feel the urge to go to the bathroom every now and again. But this particular time, I got a little start struck. Mr. Hamill had his back to me and I simple said "Mr. Hamill?" He turns around and has a almost look of horror/confusion on his face. "Could my friend and I possibly get a picture with you sir?" "Oh, yeah sure that's not a problem." So we got pictures with Mr. Hamill. He even did the Joker laugh for us!