For our 20th wedding anniversary, my gift to my husband was self-publishing a mystery that he had written. We had the book printed, many of our friends (and even some strangers) purchased it, and we had a lot of fun with the project. As far as gifts go, it was a memorable one.
One of the more interesting things to have come from this was when a Barnes & Noble (I can't even call it a local one, because it's about 45 minutes away from here) invited my husband to do a reading/book signing. He and I headed down to Marlton seven years ago today, and had a really nice time there. The Barnes & Noble said that we could keep the sign; we had it framed and it now hangs in our study.
The book is no longer in print, but the framed sign is there as a souvenir of the experience.