Former D&D player from the 1970s and 80s checks out the SCA (a week at Pennsic War), LARP, World of Warcraft (WOW), DragonCon, RenFaire, Tolkien tours, etc. to try to understand those who spend their free time in imaginary worlds. I was in the SCA for 20+ years and went to Pennsic 5 times; he did a good job of conveying what it's like to spend a couple of weeks with 12,000 of your closest friends.