(From MetaFilter): Think you’re good at it? DPChallenge offers amateur photographers the opportunity to compete in a free weekly challenge. Users submit digital photos of a certain challenge topic, taken that week, and then vote (and leave feedback) on all the other submissions during the following week, allowing aspiring digital photographers to find out just where they rank, and how to improve their skills. (And if you’d like, you can buy prints of some of your favorite entries.)