Photo: overdue underdone [Flickr]
Flickr user overdue underdone has his own "Palm Pilot" (shouldn't that be wrist pilot?) - a practical tattoo of a notebook/to-do list on his left wrist that lets him jot down notes and things to do.
Link - via Oddee, who has a list of other unusually practical tattoos
http://www.flickr.com/photos/robandstephanielevy/4668030838/