Tag Galaxy is a 3D Flex application that allows visitors to browse Flickr by entering a starting tag. Once you enter a tag, you see the tag as a 3D planet-like object, with other related tags circulating the main object. Once you select a tag to explore further, clicking on it brings photos onto the 3D object and displays them for users to browse. You can spin the globe around to browse the photos. Its a bit hard to explain, so head over to the site and explore it yourself.