In celebration of IOTD being back, I have a picture of a game engine I was working on about a year ago but never finished or submitted a shot of (named Procrastination Factor X) . more info and screenshots can be found here: http://people.haptek.com/clint/pfx/index.html
This lovely screenshot was rendered in OpenGL using simple fixed function single texturing and fog. The skybox and terrain texture were generated using Terragen. The fogcolor was carefully selected to match the horizon color of the skybox, so it looks really good in one direction and not so great in the other.
The terrain source data was from a DEM heightmap from somewhere in New Mexico I think. It used the now infamous patch-based, split-only, variance error metric, roam algorithm. Although not shown here, I was also using the Open Dynamics Engine for physics, both the character moving arround on the terrain and a bunch of boulders you could shoot. I used FMOD for sound. I used TinyXML for parsing a simple xml initialization file, terrain "atlas" file, and skybox definition file.