Again, not really unsolicited, but the late Paul Wellstone responded an e-mail I sent him. I’m sure it was written by an underling, but it just reeked of class. We are the poorer because of his death.
After seeing What Happened Was, written and directed by Tom Noonan (who also starred in it), I stopped by his website and left a message complimenting the movie and his work in Manhunter and The X-Files. I was surprised when he wrote back, and we corresponded for a little while. He’s certainly a mensch, IMO, and if you haven’t seen What Happened Was, definitely see it, but be prepared to be creeped out.
I was treasurer of the Science Fiction and Fantasy Writers of America for three years. These involved various questions about running the organization (Norman, for instance, was president at the time). Others are friends from conventions and online.
Ellison called me when I was running the SFWA Bulletin. He had written an article for us and was being paid for 1000 words. His article went over and I wrote him about paying him the extra. He called and we both got into a niceness contest (“Oh, don’t worry about the money.” “Oh, you should be paid for it.”). He won. 
BTW, if you want to talk to SF writers, go to the boards at http://webnews.sff.net. Many writers are there, and quite a few take part in their discussion groups.
I got an email from baseball researcher Bill James once.
Had to mention this, I briefly dated Richard O’Brien’s son back in college. He was very secretive about who his dad was, because he didn’t want people to know. But he looked like him, and there were the family pictures and such.
A long time ago (as you will see), I did a bit part in a summer show, **“Broadway” **starring Merv Griffin. It was one of those parts that’s so small, it is uneconomical to pay a union actor, so they would fill it with local talent.
The show got mixed reviews, but the best part occurred when we were all lined up across the width of the stage for our curtain call. Merv would then do 10 minutes or so of good standup comedy, much of which was different from night to night.
After one of the shows - maybe more - all the guys in the cast would go to Merv’s cabin to play poker. I was invited, and sitting immediately to Merv’s right, I caught the lousiest friggin’ hands all evening, and hardly played any of them. It was the worst poker session I ever sat in on. It was nickel-dime stuff so please dismiss any ideas of a scam.
Anyway, the show moves on to the next town.
Couple of months or so later, Jack Paar decides to quit as host of the Tonight Show (or whatever it was called, back then). I wrote to Merv and urged him to get in line.
Merv wrote back and thanked me, and mentioned a couple of things to show he remembered me.
The man is/was no prima donna.
Two that may qualify:
Several years ago, Slate magazine had a feature called The Breakfast Table that was a week-long, running e-mail exchange among a small group of people, commenting on whatever current news they ran across. One week it was three siblings, Jennifer, Eric and Daniel Mendelsohn. (Respectively, a Slate columnist, a screenwriter/director, and a Princeton lecturer in classics and contributor to the New York Times Book Review.) Early in the week, Jennifer mentioned an unusual type of benign brain lesion that gives people an urge to laugh, and she challenged her brothers to come up with the title that Oliver Sacks would use when writing about it. A title jumped into my head and so I e-mailed to the comments link. I got a very nice reply from Daniel Mendelsohn saying he laughed for five minutes, and he mentions it in the last installment of the column as “the single funniest thing I’ve read in years.” (This page, a little past halfway down.) Not a bad blurb from a Times book reviewer, now that I think about it.
Also several years ago, The website for one of my favorite musical groups (Uncle Bonsai, a folk trio from the 80’s) mentioned that they had found a couple boxes of their old casette tapes that they didn’t know they had. So I ordered one of each. (From what I tell, Yellow Tail Records was formed by Andrew Ratchin, the front man for Uncle Bonsai, to distribute his own music and has since signed a half-dozen or so other artists. It’s safe to call it a small label.) A couple weeks later, the phone at my desk rings, and it’s Andrew Ratchin. He wanted to know if I’d gotten the tapes, yet.
He’s probably not well known, but I saw a terrific movie last year called “Screen Door Jesus” at a local film festival. I went to their website and commented on it. A day or so later, I got an e-mail from the producer asking for details.
Bing a child of the 70s, I post “thanks for the memories” to a lot of obscure (usually female) actresses’ webpage guestbooks. Once, a former cast member of a 70s family show emailed me with a request to write Les Moonves and CBS a letter asking that she be given roles on CBS programs.
Honestly, I felt badly for her, but did not write to any of them. After that, I quit including my email in the guestbook info fields.
I won’t post her name, email me if you absolutely have to know.
Sir Rhosis
Well, I got a couple of emails from different engineers who worked on the Lunar Rover, and the German VJ-101C projects, if that counts for anything.
And I’ve had the pleasure of talking to (and working with, a bit) a Dragonlance author who frequents a fanfic message board I go to. Nice guy, great writer. Really knows how to make characters suffer. 
(But I’m not sure if I can use his real name right now–I think he might have had some legal troubles with writing fanfic using it, or something. I’ll try to check with him to find out.)
I’ve never interacted with a “celebrity”, but I’ve gotten uncounted emails from relatively famous people – I know 'em. At least I think they’re famous, if their untold bylines in magazines, film, and writing and entertainment are to be believed (but no poster-byline-worthy visual entertainment stars, although one of them has one of those in her nuclear family.)
Unfortunately, since I mainly know them online, I only know their screennames: never thought it important to ask their real names.
Jeez, no. Barbara Branden once emailed me to call me a genius for helping her with a very simple computer problem (something to do with AOL), but that, alas, was correspondence initiated by a mailing list exchange.
Had a few e-mails from Douglas Coupland over personal stuff, and one from Robert Anton Wilson about something I posted on Usenet.
Minor correspondence with Paul Quarrington, Jan Wong, and Heather Malick.
Golly, all lettered folk, now that I look at it.
Not really. I got an email from Mark Oakley the other day, but it was sort of solicited, as he was responding to my ordering a book from his website.
My Uncle got a telegram from Indira Gandhi at his funeral (while she was still Prime Minister). Apparently her father knew my Uncle at some point.
I got an email from Eve Golden about a thread I started here.
I once posted a question about a character in a novel written by Kim Newman on a message board and Newman himself read it and sent me a reply.
I’ve participated in boards where S.M. Stirling and Nancy Kress where regular members and received emails from them about things from the board.
Well, sure! The President of Nigeria sends me an e-mail every other day!
Other than that… well, no major stars have ever written me any e-mail. But New York Times crossword editor Will Shortz has sent me a few e-mails asking for help tracking down a clue.
That was unsolicited!
Beyond that, I’ve sent e-mail to political columnist Leonard Pitts (I profoundly disagreed with a column of his) and to “Luann” cartoonist Greg Evans (I pointed out an urban legend he was perpetuating)- both wrote back lengthy, thoughtful replies.
Indira sent a telegram to your Uncle at his own funeral? Could you elaborate a little, please? Is this a standard courtesy to the dead by heads of state?
I’m not being sarcastic. I’ve just never heard of such a thing.
This was about 20 years ago now, so I’m hazy on the details, but it was apparently because my Uncle knew Indira’s father, so she was just acknowledging that. It may have been during WWII, because on that day of his funeral I found out loads of things about my Uncle during that time that I had no clue about, like he was a POW. I think someone told me he was in Colditz, but I don’t know if that was true.