3D Realms' George Broussard posted this on the official forum:
"Last Saturday we had our annual company Christmas party. It was a lot of fun as usual but it featured one special surprise. It turns out that several people had been secretly working late nights and into the wee hours of the morning preparing a special video for those at the party. They created a short teaser for Duke Nukem Forever.
After seeing the teaser we thought it was something we should share with all of you and while it's just a teaser, rest assured more is coming.
Tomorrow, Wednesday the 19th, around noon CST, we will release the first teaser trailer from Duke Nukem Forever. To tide you over until then, here is a screen shot taken from the teaser.
Thank you for being fans of the game and for your continued patience."