Normally I don't put a lot of stock in rumors.  This one on the other hand has a couple things pushing it towards plausible. 

Kotaku is reporting that Gearbox Software is now working on Duke Nukem Forever.

So why does this rumor sound plausible?

Gearbox had previously been working on the now scrapped "Duke Begins" a sort of prequel/origins title.

And Gearbox Software Randy Pitchford is being cryptic with Kotaku;

"Gearbox Software president Randy Pitchford declined to comment to Kotaku on the matter, indicating that he may be able to better clarify the situation further at this year's Penny Arcade Expo in Seattle."

George Broussard, the man behind the long delayed Duke game has, so far, declined to comment.

PAX is right around the corner, so we should get news soon enough.