National Geographic has rolled out a facinating application for photographers and photo lovers. http://ngm.nationalgeographic.com/ You can upload your own photos and create your own National Geographic photo gallery page. From there, you can create assorted puzzles to play online and much, much more.
Also check out www.ngm.com/infinite where your photos and those of others make up what's known as an infinite photo - really a mosaic image made up of thousands of smaller images. Submit your photo and it could be featured as part of their next photo.