Math nerds calculate Death Star cost at $852 quadrillion2/21/2012
If you've ever asked yourself "What am I going to do with the $852 quadrillion I stashed under the sofa cushions?" (Oprah, we're obviously talking to you), why not consider building your own Death Star? According to calculations posted on Centives, a blog run by Econ students at Lehigh University, building Darth Vader's planet-destroying mega weapon would cost "roughly 13,000 times the world's GDP" and would require so much steel -- writing the amount uses 15 zeroes -- it would take more than 833,000 years to produce it.
Oh well. The second-best thing to owning an intergalactic weapon? Reading the counter-arguments in the Centives article's comment section.
What sci-fi gear would you love to have?