Have you ever lost your phone? My husband loses his phone ALL THE TIME! I was looking up fun apps and found this iPhone app called MARCO! Basically the app runs in the background, and as long as its running you just shout out MARCO and it will shout back at you POLO! You can install this on multiple devices and change the trigger phrase to anything you want for each device to distinguish them. This works even if your device is in sleep mode or silent mode. It also has volume boost even if your phone is on low volume. This is a pretty nifty app for those who tend to mis-place their phones.