Our iPhones are smart. Just not when it comes to helping us find them. Now you can locate your iPhone using nothing but the sound of your voice thanks to Marco Polo. This app listens for you to shout "Marco" — or any other input phrase you like — and responds with either "Polo" or another message of your choosing, in one of 30 unique character voices. It works in silent mode, will pop up a notification to let you find your phone in the dark, and can even boost the volume if you've got it set too low to hear. At last, no more tearing apart the couch/bed/house just to check Twitter.