The Rinspeed sQuba is the first car that can drive on land and propel through water.
This is so...Jetsons. Although, not even The Jetsons had cars that could swim (theirs just flew).
From PhysOrg: sQuba: World's First Underwater Car

"The car has a steel chassis, while its lightweight body panels are made of carbon nanotubes....An electric motor provides rear-wheel drive while on roads. Underwater, two propellers in the stern and two jet drives in the bow propel the "amphibious" vehicle. With zero emissions, the design is even environmentally friendly, eliminating any pollution into the sea...The two-seater also includes a self-contained on-board oxygen system to supply the driver and passenger with fresh air for breathing."
What are carbon nanotubes? No, no, don't explain it to me. Car talk bores me. But a car that can transform into a little submarine does sound fun. Frank Rinderknecht, CEO of the Swiss company Rinspeed was inspired by a James Bond movie to make this car. They have to be custom made and I haven't been able to find a pricetag for it. I think that means only the wealthiest of the wealthy will be able to afford it. Rinspeed can also rightly claim the title of Coolest Car Company in the World. Check out some of its other cars here.
I'll share with you my own little sQuba fantasy (if I were as rich as someone like Bill Gates): I'd drive up onto a beach, making sure there were alot of people around, then just drive it right into the water. I'd propel around for about five minutes, giving everyone on the beach time to freak out, then I'd drive it back out onto the beach. THEN, I would get out of the car and say, "What? It needed washed."
And they say money can't buy happiness.