Of COURSE Greg Irons' illustrations for Gary Gygax's D&D coloring book are a bit too advanced for little kids; it's got Advanced right in the title! What are you, -5 Intelligence?
Giant, colorable scans of The Official Advanced Dungeons and Dragons Coloring Book - Illustrated by Greg Irons (1979) [monsterbrains via boingboing]
Independent but completely related, because it's about adult/parent nerds: Matthew Baldwin's epic report from PAX Prime, a gigantic gaming con I'd never heard of, but which I busted out laughing while reading about [themorningnews]
I had that! Wow, you just woke up some long-forgotten brain cells.