When I was a second year student at NESOP, I had an assignment in Advanced Black & White class to photograph in low light.
I had heard that David Boreanaz (at the time, Angel on Buffy the Vampire Slayer, now he's Agent Booth on Bones) was going to be signing autographs at a store in the Prudential Center. I was (and still am) a Buffy fan, so part of me wanted to go for that reason. Then I realized that I could use the event for my assignment. I assumed (correctly) that there'd be some crazy fans waiting in line, so I decided to document the scene.
I waited in line just like everyone else, and photographed the fans and their posters, pictures and books etc., that they brought for David to sign. I remember when I got to the front of the line, he was friendly, and gladly posed when I asked if I could take a photo of him. I had my crap 70-210 Quantaray lens, and about 5 seconds, so I was extremely lucky to get what I got!