[Rosenberger31] did a nice job of adding a USB port to his 2010 Toyota Prius. He removed the access door on the console where the traditional “cigarette lighter” 12 volt port is located. A Dynex 12-volt to USB adapter was piggy-backed onto the power lines and the USB connector was then fit into the blank accessory plate next to it.
There is no data connection here, the port only provides 5v regulated power to devices plugged into it. None the less, it is still a pretty nice looking alternative to having a power adapter hanging out of the dash all the times. If you try this, heed one of the warnings from the comments and make sure you add a switch if you vehicle powers the 12 volt port even when the car is not running.
This makes us wonder: will this void your warranty?
[Doug Heffron] modified this 1989 Geo Metro way back in 1993. Gas prices had just started breaking $1.00/gallon and he wanted to show manufacturers how to build a fuel efficient vehicle in such troubling times. The car already got 58mpg (Prius: 46mpg), but [Doug] decided he could do better with some aero modifications. The car was converted to tandem seating and stripped of any extra weight. In its final form, it got 75mpg, but then gas prices stabilized and it was laid to rest in a shed. You can find out more about the car and see photos from the build on its site (painful resizing).
Adding extra battery capacity to hybrids is becoming pretty common, but this one is better than the average lead acid trunk fest. The pack was built from three prius NiMH packs picked up from salvage yards. These batteries can’t simply be bolted together, but with some research and effort you can save some nickel from the junk yards and cut your fuel bill.