I've had brushes with many, many celebrities in my day. A few impressions:
Jim Carrey - indirect brush with fame, but my best friend during high school was his cousin, so she had lots of family photos with him in them. He was quite cute as a little kid - she even had photos of him making funny faces.
J Lo - at the height of Benniferdom, was rehearsing in the dance studio across the street from where I worked. I saw her most mornings wearing a velvet track suit with no make-up on and ratty hair, looking very tired
Keifer Sutherland - during his post Julia Roberts, pre-"24" days when he was "washed up." At a patio bar - he was totally wasted, his (now ex) wife sat angrily at the end of the table, his two little boys asleep under the table. Then I saw him again the next day, (it was Canada Day in fact and he was giving a little speech at the unveiling of this chime clock) clearly hung over.
Sam Neil - my closest actual "brush" with a famous person, I was biking to work down a street they were filming on. Since there were so many trailers in the street I had to use the side walk. As I whizzed along he stepped out of his trailer directly in to my path then leapt out of the way. Him: "Hey!" Me: "Sorry!" Later at work I'm thinking, "hey I almost ran over the guy from 'The Piano.'"
Keanu Reeves - played, and no I'm not kidding, "Hamlet" at the Mantioba Theatre Centre. He was nice enough to stop and chat with my bestfriend, who had a broken leg at the time. The play was, needless to say, fairly embarrasing. The newspaper wrote a somewhat mean-spirited article about it, referring to my friend as "gushing."
The President and First Lady of Portugal - I worked at an art gallery, and they had a private tour of the facility. Several secret service men. I remember shaking the president and his wife's hands and thinking, there are probably people in the world who would love the privilege of meeting these people, or maybe their totally hated, who knows, but this has no real significance to me, and I wish I didn't have to be here.