Windows only: Photo! 3D Album creates virtual galleries for your photos, walking through them with a first-person view not unlike a video game.
Once you've installed and launched the application, you can choose the type of gallery you want—mountains, art gallery, cathedral or many others. You then pick the pictures that you would like to include in the gallery, and you can preview the gallery in first-person mode, walking through to admire all of your pictures. The graphics probably aren't up to par with any modern video games, but it's still a novel way to show off your pictures.
After you've finished perfecting your galleries, you can export the files and then assign them under the Photo! 3D Screensaver under the regular Windows screensaver settings, or you can also export them as an .exe file to share with others. Photo! 3D is a free download for Windows only.