When you're vacationing on a beach, nothing beats an underwater camera; but watertight cases are pricey and disposables have lousy quality. Lucky for you, the editors of PopSci have come up with an easy workaround using something there's probably already plenty of in your suitcase (hint: not socks). That's right, thanks to the magic of unlubricated condoms, you too can transform your point-and-shoot into an waterproof wonder. The set-up is easy enough, but as John and Doug demonstrate, it really does help to have a partner lend a hand.