Wireless dash-mount car charger. Love this thing.
At work, I use custom maps on my phone to guide me to the next spot, get out of car (with phone) for ~4 minutes, then get back in and go to the next spot. Screen is always at full brightness and I use the damn thing all day, so it would always die in the afternoon because I got sick of carrying around the USB pack with me. This thing is awesome because I just drop the phone back in the holder when I jump on and it still has enough time between stops to put a couple more % on the battery.