Not sure if it counts as "famous", but I met Joan and Walter Mondale when I was in 5th grade. I was hanging out at the service station where my stepfather worked and they came in to get their car fixed. I've always been a politics geek and for me, it was like meeting a rock star. I went to their house once and spent an afternoon playing with their dog Digger. For my 10th birthday, Mrs. Mondale sent me an advance copy of a family cookbook she was publishing and it was autographed by both of them. It was my most prized possession until my ex-husband's dog got a hold of it and chewed it to pieces.
I also met the late Senator Paul Wellstone twice. He was my idol. George Stephanopolous gave a speech at my college. He's much tinier in person, and better looking.
In the late 80's, when I was 8, I did a thing called the Multiple Sclerosis Read-A-Thon, and was the 3rd top money raiser in the state of Minnesota, and got to meet a bunch of local sports celebrities (Vikings, Twins and North Stars players) and was in a commercial with a few. I had no idea who any of them were and my mom had to point people out to me to get autographs. I had a professional portrait done of me and Matt Blair (Vikings player) and it was matted and framed by the team with the Vikings logo. I gave it to my dad, and he had to show it off to anyone that ever came into his house lol.