I made this Valentine card a while back for the purpose of sending out a hint. It works every time.
Oh, and just for the heck of it, I'm linking my favorite chocolate store in San Francisco. They have an entire data base of the finest chocolate ever made and they email secret hidden words to you that will get you a free bar of chocolate when you follow the directions. Maybe since I gave them a free link, they'll throw a truffle or two my way? Medium: Ink on paper, digital color.
UPDATE: It worked!