Bastards! 
[ul]Alton Brown
[li]Mario Van Peebles[/li][li]MC Hammer (when he was still popular—his style of dress was not just for the videos)[/li][li]Chris Rock[/li][li]A number of professional baseball players and professional bowlers[/li][*]A number of local TV and radio personalities[/ul]
Pretty sure we’ve done this multiple times over the years.
http://boards.straightdope.com/sdmb/showpost.php?p=17869141&postcount=123
More recently, met Will Smith and his entire family at a restaurant in NYC last month.
Famous
John deLancie
Bruce Campbell
Felicia Day
Katie Sackhoff
Billie Piper
Wil Wheaton
Christina Applegate
Bobby Mcferrin
Less Famous
Colleen Atwood
Geoff Notkin
Warrel Dane
Jeff Loomis
Michael Stackpole
Scott Kurtz
I’ve met a lot of people at conventions and the like, but these were often very brief introductions and no more. Some I’ve spent more time with. A very few I spent a lot of time with .
Lotta Time:
Arthur Kantrowitz – founder of Avco Everett Research Lab, inventer of many things, president of L-5 society.
Lee Moyer — fantasy/sf artist
Talked with for quite a while:
L. Sprague de Camp
Jack Kirby
Orson Scott Card – he even critiqued one of my stories
Brief:
Harlan Ellison
Isaac Asimov
Elizabeth Warren
Harry Turtledove
There are plenty of others I’ve just shaken hands with, or attended lectures. More than I can count, actually.
Along those lines, Nina Hartley, but also Peter North, Christy Canyon, and Janine Lindemulder … but not all of them at the same time. That would’ve been… weird!
Yeah, that’s one way to do it. That’s how I met Bruce Campbell, Kenichi Sonoda, Adam Warren, and the stars of The Karate Kid: Ralph Macchio, Billy Zabka, and Marty Kove.
Cybill Shepherd, Steven Segal, Al Green, and Mark McGwire.
I think the word you are looking for is orgy.
My tiny list:
Felicia Day (drive to Portland & Seattle for her book signings last year.)
Tanya Tucker (back when she was still a teenage sensation)
Hal Clement (got tongue tied trying to talk to him)
James White (same)
Anne McCaffrey (and again)
Frederick Pohl (there is a theme here)
James Doohan (he sat for hours smiling and talking until everybody in the line got through)
Neil Gaiman (back to the theme)
Terry Pratchett (such a wonderful man I was able to chat a bit)
Katherine Kurtz (several nice chats with her)
Harry Turtledove (never said anything, couldn’t get a word in edgewise)
George R. R. Martin (fun to talk to, DON’T ASK ABOUT THE NEXT BOOK. Really)
Kate Elliott (absolutely wonderful to talk to, don’t get the chance very often)
Lots of other SF&F writers. Conventions are wonderful things. Oh, Kim Stanley Robinson, really friendly, nice to talk to, so is Jack Campbell (John Hemry). And I better stop.
Donnie Osmond once had me thrown out of a radio studio.
Robert Goulet told me I needed to zip up my coat one winter when I passed him on the streets of Louisville, Kentucky.
Ajay Naidu, who played Samir in “Office Space,” sidled up next to me in a bar in New York City.
George Carlin
Del Close
The bands Ratt, Tesla, Nikki Sixx from Motley Crue, Lita Ford
I called Michael Stipe a “cocksucker” to his face.
I met Jennifer Lawrence once, but it was years ago, and I didn’t have any idea who she was (this was before she because well-known).
Is Robin Curtis famous enough?
Details, please!!!
I totally forgot one:
When I was about 12, I had a lengthy conversation with Sir Edmund Hillary.
Katherine Hepburn
Bette Davis
Gregory Peck
Van Johnson
Robert Mitchum
Robert Redford
Paul Newman and his wife Joanne Woodward
Sidney Pollack
Mel Brookes and his wife Ann Bancroft
Robert Redford
Princesses Caroline and Stephanie of Monaco
Lord Grade - British media proprietor and impresario
Mollie Sugden - British actress, played Mrs Slocambe in Are You Being Served
Anthony Valentine, actor, starred in UK TV productions of Colditz and Raffles
Tom Stoppard, playwright and his wife Dr Miriam Stoppard
Ed Stoppard, actor, son of above
Daniel Day-Lewis and his mother Jill Balcon
Barbara Knox, William Roache, Bill Waddington - actors from popular long running UK soap Coronation Street.
I sold a hand held device to Slavoj Žižek if that counts …
I’ve met a ton of Broadway actors at stage doors.
The famous people who know me include Bruce Harper, Brenda Blackmon and Rudolph Isley.
None to speak of. A bunch of my friends meet a lot of celebs at conventions, but I don’t go to those, and my life is not very social, so nobody of note has passed my way.
Back in the '80s I went through a revolving door with John Lithgow. Ah, the crazy '80s.
After college I was roommates with Bob Christian, who went on to become an NFL fullback with Carolina and Atlanta.
N.T. Wright, British theologian and author.
As I kid I shook hands with Ted Kennedy.
Debbie Thomas, Kristi Yamaguchi and Surya Bonaly (figure skaters)
Jeremy Paxman (UK TV presenter)
I sat next to Festus Mogae, the former president of Botswana, at a formal dinner. He was a lovely gentleman!
I don’t know how famous they are, but I went to high school, and acted in plays, with Zach Gilford (Matt Saracen on Friday Night Lights) and Jessie Mueller (Tony winning actress who played Carole King in ‘Beautiful’ and is currently starring in ‘Waitress’).
I was invited to an odd dinner party where the host hinted at a famous personage who had been invited but was not clear on whether he was going to show up. Alas, he didn’t, because otherwise I would be able to say I met Boris Johnson (currently disgraceful UK politician). I can only hope I would have said something devastating witty and insulting to him if he had shown up…
Garret Popcorn?
You sure know how to tease us.
Let’s see …
As a Cub Scout I got to meet Washington’s then-Governor Dan Evans.
Former NFL player Manu Tuiasosopo was the guest speaker at a Christian men’s dinner I was for some reason invited to in my 20s.
In 1990 I met former NFL player Ervin “Blueprint” Parker when he came into the restaurant where I cooked at the time. He ran some anti-drug program where he would bring current NFL players to schools to talk to the kids, and he was scouting places to bring the players for dinner. He picked our place, and I ended up, a few weeks later, getting to be the one to cook steaks for several Seattle Seahawks players. I got to meet them all and have my photo taken with them.
In 1996 or so I met Joey Cora, then the Seattle Mariners’ 2nd baseman.
I have met former Tool bassist Paul D’Amour (his parents attend the same small church I attend). However, I met him when he was still in high school, so I’m not sure if that counts.
In 2006 I met Montana’s then-Governor, Brian Schweitzer. Made a thread about it.
I’m not sure how “famous” she is, but I’m closely related to well-regarded children’s book author, Barbara Jean Hicks. We haven’t actually met in person (unless it was when I was very young), but we’ve communicated via Facebook and she has read and evaluated some of my amateur writing.