As in, named in the Acknowledgments of a published work?
Because I just have and it’s awesome!
It’s a scholarly work of little interest outside of a very specific area, but that matters not at all to me. I had no warning whatsoever, it was a complete surprise, and a delightful one at that!
Not myself, but I have a family member who helped with some research for a Tom Clancy novel and was in the acknowledgements, by first name. I got copies of a couple Clancy books signed to me by name.
I was thanked by Rick Boyer in one of his Doc Adams books.
Several times, some special interest and some not. Most recently in a series of birdwatching books.
I’m a helpful guy.
My name is in the liner notes of a few CDs. Not huge releases, but still cool.
a couple of instructional poker books (available at your local bookstore) and various academic theses (which I guess are only quasi-published)…
Yes, a handful of times, once rather fulsomely. It is all very obscure academic stuff, though, with the partial exception of an undergraduate textbook (not the fulsome one). I doubt that it sold hugely, but it did go into a second edition, so there must be a few copies around.
I tend to get more chuffed about my work getting cited, rather than me being acknowledged, even though many of the citers often seem to have completely missed the point of what I was saying, sometimes to the extent that it seems inconceivable that they can have read past the title.
Yep, I did some research for one of my profs for a book he was writing and I got a mention in the acknowledgments. It wasn’t unexpected but it took him a few years to write the book, so when I got an email from him to let me know about it a few months ago it was still a nice little surprise. And it’s probably the closest I’ll ever get to having my work published 
The wife and I were once singled out for special acknowledgment at the front of one of the Lonely Planet Thailand guides. And I don’t mean the section in the back where they automatically list the name of everyone who wrote in comments and suggestions, although we are often found there too.
I got an ackowledgement in my brother’s first published novel.
I also have songwriting credits on a couple of CD’s.
An article of mine was cited as a source in a doctoral dissertation.
I’m on the dedication page of an obscure scholarly historical work about the Hapsburg monarchy.
I have a friend who was thanked by Neil Gaiman at the front of one of his books.
I’m mentioned in the acknowledgements for the reprint of Ray Bradbury’s Dark Carnival. I did the first proofread – comparing the original with a re-typed manuscript. I found lots of goofs, as would be expected.
My mom died while I was working on it, and I only managed one run-through. I’m afraid to re-read the book, because I don’t know if anyone else looked at it after I did, and I saw at least one typo in the acknowledgements. I hate typos, and I really love that book – it deserved to be perfect but I’m afraid it isn’t. 
I’ve been credited on a couple of websites under my other internet identity. Under my real name, by the end of this year, I expect to be listed as Appellant’s Counsel in a published decision. Hopefully, a decision in my client’s favor.
Oh wow…I also have a friend who was acknowledged in one of Gaiman’s books!
I was acknowledged in an English-language guidebook to a popular theme park in Tokyo.
And I was also mentioned in the liner notes of a CD which featured music related to the same theme park.
Yes I have. I’ve been named in the text portion of books, in the forward, and in the bibliographies. Of course, the books are pretty obscure and unknown to everyone outside the field I’ve done my work in.
I’m acknowledged in two popular fantasy novels written by a friend of mine. The first because we wrote a story together when we were younger, and the second because I helped proofread it.
Hmmm…given your hometown, it’s quite possible that it’s the same friend! Was it in Anansi Boys? And does your friend live in L.A. now?
Ooops, just checked and it’s in the Afterward, not the beginning, of the book.