Worldwide Pinhole Photography Day

It's World PinHole Day on the 30th of April - If you don't have a pinhole camera, you can make one, or you could use an SLR or Digital SLR and make a pinhole lens to go on the front of it.

"They hearken back to a simpler time when a camera was literally just a box with film in the back. Photos made with pinhole cameras exude a fuzzy, low-fi charm that’s hard to resist. That said, it’s not for everyone, but I hope you’ll give it a try." - Photodoto Guide

Here's some links that you might find useful:

PinHoleResource.com
Pinhole Tutorial
Canon 1Ds as a Pinhole camera