You've already seen the famous fan-made Portal Gun. Now see the entire build process documented in 113 photos (OK, only about 40 of them actually showing the gun in its raw clay form).
There aren't any clear instructions detailing just how to build your own gun, but you're way too lazy to ever actually build a recreation. Luckily, if you're sitting on a small mountain of cash, you can go to the creator's site for any business inquiries. Apparently, Portal's developer Valve has ordered a model. And if you're willing to stand in line long enough, maybe you could score one, too.
See all of the build photos here: [GameDaily]