The first Duke Nukem Forever DLC details have landed on the Gearbox forums , picked up by VG247 . It will be called the Parody Pack. It will add three new game modes, four new maps and new weapons designed to send up a few well known, slightly more successful shooters.
There's Call of Duke, a modern combat map populated by N00b T00b launchers, 2Forts1Bridge, with its own Heavy style minigun, and two other maps featuring sticky bombs and a weapon known only as the "DFG."
The DLC will be out this Autumn, and will be free to the First Access Members who pre-ordered Duke Nukem Forever before its release. Two screenshots have been released along with more DLC details, which you'll find below.
Here's a summary of the Parody Pack's innards, as supplied on the Gearbox forums: