What has been your favorite moment not as a writer,
but instead as a reader and fan or other writers?
This one is probably the easiest question I've ever had to answer (other than telling a certain Lisa Evans -- at the time -- "I do" that is).
Hands down it's the time I met Ray Bradbury at my very first Dragon*Con. I waited in like for what seemed like an eternity, watching as fan after fan got to say hello (barely), get a book signed, then be ushered away by the attendants. When the hour passed and I finally stood across the table from the great Bradbury, I told him what an honor it was to meet him, handed him a bedraggled mass market paperback copy of The Illustrated Man (because I couldn't find my copy of The Martian Chronicles at the time), and as he signed it, I told him I wished I'd brought my reprint of the "Mr. Electrico" article for him to sign instead.
About this point, the attendants politely let me know I was taking too much time with him, and he looked at me, said thanks for reminding him about "Mr. Electrico" and quickly finished scribbling his signature and handed me back my book.
After that, I walked on clouds for the rest of the week.
Here's a link to a 2001 recollection of "Mr. Electrico" from the reigning prince of sci-fi himself.