Melissa Joan Hart, when I was in middle school. My school was involved in something for Nickelodeon (I don't remember what). All I really remember about her was that she seemed very tall... but I was a short kid until I turned 15.
Anna Nicole Smith was on the same plane I took to Louisville, KY in 2003 (puddlejumper from St. Louis, MO. Not sure why they put that layover in there). I was headed to Ft. Knox for basic combat training. She was headed to the Kentucky derby. What I remember most about her was that she was drunk, fat and belligerent. She refused to sit down while the plane was landing, and her bodyguards looked very embarrassed.
A friend of mine used to work in the kitchen at the place that Art Alexakis went bowling regularly. I used to hang out there while waiting for my friend to get off work. Art seemed like a pretty normal guy, the few times I talked to him... though ironically he drank nonalcoholic beer with his meals there.