Uboatworx CQ-2 Two Passenger Personal Submarine
Two nice things about this submarine, the first is it stays pressurized at 1 atmosphere, or basically what it is on the ground. The second is the fact it doesn't require fuel, its all electric.
Two bad things are, the 2.5 hour battery life, and the 14 hour charge time. But 2.5 hours in a submarine is probably a rush that is worth the 14 hour wait. There are 4 motors, two for thrust, or forward motion, and one for up and one for down.
There is already a one-seater version out, and there is a 4-seater version expected some time in 2008. There is a pre-requisite training course for the submarine before you can take delivery of your very own. Having that pleasure however will cost you just under a quarter-million dollars.
The CQ-2 twin seater personal submarine [via gizmag]