A lot of cars today have handy USB chargers in the backseat so that people sitting in the back can charge their gadgets. Of course, older cars don't, which is why Instructables user wongman2001 decided to install his own.
The installation uses a cigarette adaptor and terminal connectors to wire in all the cables. The charger threads through the seat so it ends up looking clean and natural in the back. That also means you'll have to take the seat out to install this, but it doesn't look too difficult.
Head over to Instructables for the full guide on how you can do it for yourself.