I just sealed a letter to Zach Galifianakis, the first piece of fanmail I have sent in probably 8 years, and I am about to pen one to Quentin Tarantino. I used to write people all the time, though (little came back in the mail from them). I remember writing to Emma Watson around the time Prisoner of Azkaban released because that’s when she started to become hot in my eyes. I got back a hand written letter with a hand written address and hand written autograph. Needless to say, it was insanely awesome. I also wrote a super cringe-inducing letter to Dub-ya and got a halfway stock letter back.
Yes. I’ve sent mail to (and gotten replies from) Dave Barry, Martin Gardner, Philip Klass, and others. I’ve e-mailed Christopher Moore and got a response almost immediately.
we’ve had threads on this in the past – several Dopers have corresponded on at least a limited basis with celebrities.
And some have worked with them.
Yes, and I was really disappointed by the lack of response. Shall I tell it here? It’s pretty dear to my heart.
When I was much younger, I was having major troubles with the fact that I’d been adopted and born out of wedlock. In my early twenties I realized the Indian movie “Lawaaris” spoke very closely to my situation - only he had a far worse life than me, literally rejected by everyone he loved.
I wrote the star of that movie, Amitabh Bacchan, a long, heartfelt letter, in painstakingly written Hindi, about how much his portrayal of an illigitimate child meant to me, and how important these kinds of issues were to thousands of young children.
I got no response back. Not even a signed poster. 
I used to do it a lot when I was younger. I never got any personalized response, except from John Noble, who was very nice and appreciated my thoughts on Denethor. I did get autographed photos back from David Duchovy and Gillian Anderson, and they appeared to be handwritten autographs. This was in the first year of The X-Files, so I always figured they weren’t getting flooded with mail at that point and could take the time to sign a photo.
Not so much a celebrity, but I did once email a model I saw in a internationally distributed magazine. We exchanged a few emails and I went to a party at her house once. Lest it sounds otherwise, this was all purely platonic.
I have written to a few, but if you are wanting to know if who I have written to has written back to me, no they never did…until Twitter came along! Thanks to Twitter, three of my most favorite singers have written back to me at least once: James Otto, LeAnn Rimes, and Darryl Worley!!! 
God bless you and them always!!!
Holly (a day one fan of Darryl and LeAnn)
I once wrote Mariska Hargitay, who plays Detective Olivia Benson in Law and Order: SVU to thank her for her work in bringing rape and other sex crimes to the forefront and supporting charities to help rape victims. At the time, I was close friends with a woman who’d been raped years earlier and still struggled with some of the damage done to her. It meant enough to me that I even knitted her a scarf out of alpaca yarn.
I got back a nice form letter and an autographed picture. Still have it around here some where.
I wrote to two authors, James Michener and Spider Robinson. Got personal replies back from both of them. Not long notes, but not form letters. And Robinson told me that my guess as to who the first person narrator in Callahan’s Lady looked like was correct
I had a pretty good back and forth email conversation with Steve Wozniak about fourteen years or so ago. He was caught up in the aftermath of Pirates of Silicon Valley, a TV movie about him and Steve Jobs, among others, and due to his personal value system he was responding personally to everyone who emailed him. It put quite a strain on his marriage as he wound up emailing sixteen to eighteen hours a day and still couldn’t keep up, and that went on for several month. I didn’t know about any of that at the time we started corresponding though and only found out about it when he apologized in advance for any delay I might experience in hearing back from him, although I usually heard back within a day or three.
We talked about a wide range of stuff, from the state of the computer business to the state of modern day education, and about some of his practical jokes and some of his life philosophies. He’s a pretty cool guy. He obviously enjoyed our talks as he had a link on his site where he would post his favorite exchanges by email under a heading called “Letters” and he posted a couple of excerpts from mine and his answers to them among them.
Our conversation went on and off for about three weeks or so and then I finally decided to cut the guy some slack because he started posting entreaties on his site seeking to cut down on unnecessary emails.
I’ve always thought highly of him since then. I don’t think he comes off as well on TV as he does in private conversation. He can seem sort of scattershot and flighty on television, but I think that’s just because his mind is so quick and he talks so fast: he has lots going through his mind at one time. But he’s really a very thoughtful and principled person, and very interesting to talk to one-on-one.
The guy who played “the Todd” on Scrubs wrote me back when I emailed him. He was nice.
Dave Barry responded to a letter I wrote to him in a column – I think it was only an online column, though.
I have also emailed a couple of times with Ben Stein, and once with Scott Adams.
I wrote a letter to Isaac Asimov when I was a teenager. He sent me a postcard in reply.
In '76–'77, I wrote a letter to Charles M Schulz, telling him how much I had enjoyed one of the Peanuts specials and asking about the music. I got a nice thank-you note signed by him in reply.
I didn’t realize at the time that an acquaintance of mine in St Paul, Dr Sherman Schultz, was a long-time friend of his (Shermy in the comic strip was named after him). Dr Schultz would later be a mentor of mine in college.
I sent Regina Spektor a Hanukkah/get well card (she’d injured herself during a vertigo spell) five years ago, and one of my childhood crushes got a 60th birthday card last year. Neither wrote back.
A celebrity has written to me. Does that count?
I read an anecdote by Paul Newman. He said the best letter he ever got was from a guy who said, in essence: “I really like your spaghetti sauce. My wife tells me you’re also in the movies. Do you have anything on VCR?” Newman framed it and hung it to remind himself to keep his ego in check.
I’ve never written to anyone more famous than a basketball coach at a little-known Division I university. I was in high school at the time. I actually got a handwritten reply back, and I still have it.
Now that I’m an adult, I would NEVER, EVER even *consider *writing a letter or email to a celebrity.
Hmmm. I see Ke$ha’s fan mail address is a P.O. box in Nashville, the town where she grew up. Very tempting…
I sent fan letters to all kinds of TV stars in the 60s. The replies were mostly studio headshots, sometimes with autographs.
I wrote a gushing letter to Pete Townshend in 1983 and got back a note saying “Thank you for your kind and touching comments”.
George Allen: a letter about a million years ago, and got a letter back thanking me for being a Redskins fan living in Dallas.
Author Carol Shields: a letter about the book Swann commenting on some links to Proust, and she wrote me a nice letter back.
Stephen King: I sent a letter many years after a nice conversation with him, and his assistant wrote back and said if he answered all those letters he wouldn’t have time to write the books I presumably love.
I keep wanting to write Pete Townshend but I figure he gets thousands every year and I don’t know where to send it anyway.
lol. I don’t even know what to say about that.