Thanks to Matt Forbeck for pointing this one out.
Now for a brief cheat sheet to some, but nowhere near all, the jokes.
GenCon is the largest gaming convention in the country.
Len Lakofka wrote two of the early Dungeons and Dragons modules Secret of Bone Hill and Assassin's Knot. These adventures were known as the Lendore Isle series because of their location on the Lendore Isles on the World of Greyhawk. Assassin's Knot was one of the modules that first introduced me to true city based gaming and was innovative for its abandonment of the traditional "dungeon crawl" motif. These modules marked the first time that modules began to simulate narratives rather than tactical wargames.
All Paladins have to be Lawful Good.
There is no "Save vs. Psionic Attack." The appropriate save would be "Save vs. Spells" or "Rods, Staves, or Spells" depending on whether he was playing Basic or Advanced Dungeons and Dragons.
[Edit: After looking through my 1st edition DMG, I must correct myself. There is indeed a save vs. "Psionic Blast" for non-psionics. The implication then is that Coulbert's Paladin was a non-psionic character. Naturally this is a testimony to his honesty, and fairness, as a player. After all if your 21st level Paladin is non-psionic you can't be a munchkin.]
The idea that a "Cure Light Wounds" spell would be used on a 21st level Paladin is itself funny.
Tenser is a powerful mage in the World of Greyhawk.
The Sheldomar Valley is on the World of Greyhawk.
Displacer Beasts, Mind Flayers, and Beholders are creatures unique to the Dungeons and Dragons game.
By Stephen's difficulty pronouncing the names and places, it is likely his writers didn't go to "Exorcism Summer Camp" or find girlfriends.