Nope, it's not a car, but it is a means of transportation. We've covered it in the past even. It's the Sun21 solar powered boat. They made it back to New York after their first Atlantic crossing. Note that they used nothing but power from the sun, no wind or petroleum fuels were used at all. They were able to store excess solar energy from the sun in batteries so they were able to continue their relaxing cruise all through the night. Doesn't sound like too bad a way to spend some vacation time, to be honest!
A note that caught my eye from the source article: Does this solar powered boat prove on a small scale what could be possible on a large scale for our transportation needs? Feel free to discuss.