Someone stumbled across a screenshot on 3D Realms’ website that has been confirmed as an in-game shot from Duke Nukem Forever.

I played the original Duke Nukem’s and don’t know exactly what the big fuss about this is. The game has been in “production” for about ten years now so no one but the people over at 3D Realms know what is happening with it.
The President of 3D Realms had this to say about it:
I guess I’ll reconfirm what I said last night. That’s an in game, real-time shot of Duke standing in a random hallway. It was really done as a small teaser for a job ad on Gamasutra.com. Nothing more.