Most of it goes to Congress-approved discretionary funding—a pile of money that pays for stuff you'd never OK if you were in charge, including a lot of intangible salaries and upkeep. But that's not all. A hefty chunk funds awesome R&D and sci-fi toys that'll make you proud to be an American. So this April, as you spend late nights scrounging through shoeboxes of old receipts, take comfort in the knowledge that your cash is helping Uncle Sam launch space telescopes, make new maps—and build POTUS a fleet of tricked-out new helicopters.