The fifth and final Fallout 3 DLC, called Mothership Zeta, will be available on August 3rd on the Xbox Live Marketplace, as well as Games for Windows Live, for 800 Microsoft Points. It will be released for the PS3 at a later date. Here’s the synopsis from Bethesda:

Defy hostile alien abductors and fight your way off of the massive Mothership Zeta, orbiting Earth miles above the Capital Wasteland. Mothership Zeta takes Fallout 3 in an entirely new direction – outer space. Meet new characters and join with them in a desperate bid to escape the Aliens’ clutches. To do so, you’ll wield powerful new weapons, like the Alien Atomizer, Alien Disintegrator, and Drone Cannon, and deck yourself out in brand new outfits, like the Gemini-Era Spacesuit and even Samurai Armor.

You can color us excited. Now we know that the alien crash site was meant for more than just finding the fantastic Alien Blaster weapon. Who’s excited?