Gibson Self-Tuning Guitar
Saw this on Gizmondo recently - a Gibson self-tuning guitar. There's also a nice Technology Review write-up on it.
Basically, it's an add-on that Gibson will install on any guitar for about $900. At first I thought that sounded like a lot of money to be too lazy to use a tuner, but then I realized for a working musician this is a hell of a lot cheaper than buying a second guitar for alternate tunings.
That's a great gadget. Now they are exclusive to Gibson I imagine that its no longer available for other models as per the original website but there's a excellent video that shows it in action