Erik Ruhling is author of the book Infernal Device: Machinery of Torture & Execution, a visual history of such devices as the Iron Maiden, Guillotine, Tongue Tearer, and Ear Chopper. I've just discovered that Ruhling also created The Torture Device Coloring Book. It's available for download for $3.44 or as a print-on-demand from Lulu for $8.85. The 20 drawings are accompanied by a rhyme. Sounds like more fun than a barrel of rabid monkeys!
Link to buy The Torture Device Coloring Book
Link to buy Infernal Devices: Machinery of Torture & Execution