The Rasterbator!

The Rasterbator is a little online tool that creates ginormous, rasterized images from any photo you upload and then spits them out in pdf format. All you have to do is use somebody else's printer to print all the pages (it's a little hard on the ol' ink cartridge), painstakingly tape/glue all the pages together, hang up your piece of art, and admire! Neat!