portable 12v air compressor
 

does anyone keep one in the car. any good ones ?

I bought one from Target. $14.99 and it plugs into the cig lighter. Great little thing to air up tires.

I don't keep it in my car, but I've got one. Best Xmas present I've ever received.

However, on the trip to the Dragon I'm about to take, it will most certainly go into the front trunk. Not heavy, doesn't take up a lot of room, and is indespensible on a trip when you need it.