If you're ever out walking around the streets of New York, Los Angeles, Chicago, or Boston and your smartphone is running low on juice, you may want to check out a bus shelter or two.
Ad agency Crispin Porter + Bogusky, has put together a bus shelter advertisement that pushes Vitamin Water. They key difference between this ad and other ones that you may ignore is that this one has a 5V USB port that will allow those nearby to plug in their chargers to power up their iPhones, Androids and other mobile devices.
Of course, the shelter just provides the USB port, so it's up to the person on-foot to bring his or her own USB cable. Mind you, users should always be careful about putting their plugs into unknown ports -- though the bus stop seems to be a fairly safe place to do it.