Joao A. Carvalho is an artist who draws amazing 3D notepad art. Many of his pieces play with the blue lines found on most notepads (most are actually manually drawn), bending and twisting the lines to give the characters depth. Once the shading has been done the characters almost look as if they could jump off the page.
To see more of his work check out his Facebook page.
Believe It Or Not This Notepad Art Is 2D