I saw this and thought it was a great idea!

You are traveling in the car, and your cell phone is dying. Just plug it into the window! You go to the coffee shop, and there are no sockets available to plug your laptop in. Now you can just plug it into the window!

Yanko Solar Window Socket (Kyuho Song & Boa Oh)

These aren't available in the U.S. just yet, but hopefully they will be soon!

Yanko Solar Window Socket (Kyuho Song & Boa Oh)