Star Wars's Death Star. You know you want one. You'd feel safer if the Air Force had one. Admit it. But given all the arguing going on about the deficit, someone had better run some serious numbers to figure out (a) can we afford it and (b) would it be worth it? Fortunately, there's a discussion going on about those very things. Here's a good place to start. It's one of the later posts, but if you click backward, you'll get the whole conversation. My favorite comment, posted on a piece by Kevin Drum:

"Come on! They built one for the movie! That didn't cost 1.3 billion times the planet's GDP! Or did it? Is that what caused the housing crisis? On that same note, the Death Star is not something we'd need while we have bankers. Just infiltrate a couple of bankers onto a planet and kablam! whazoop! the planet is destroyed. "

Image: Wikipedia