Hand-Drawn Game Guides is a project by Philip Summers that is exactly what it sounds like. Summers illustrates guides and maps for retro video games, such as Legend of Zelda, Mega Man, and Contra.
My video game phase as a kid was relatively short-lived, but I was partial to Ninja Gaiden for a good while. Summers provides a free guide for the game:

[via kottke]
Visualize This: The FlowingData Guide to Design, Visualization, and Statistics (2nd Edition)
