has a nice roundup of images from April Fool's Day 2012, including this one of an ad by Hipstamatic (an iPhone app) for contact lenses that will give everything you look at the warm glow of a vintage photo. (Thanks, Bob!)
INTRODUCING: Hipstamatic Contact Lenses. See the world through the shadows of John S, the sexy glow of Lucifer, the dreamy haze of Loftus--and many, many more. Inspired by the beautiful effects of our HipstaPaks, these babies will rock your world. Pop them in to make every moment extraordinary.