Check out this jet powered beetle....
To quote Thomasnet... VW Probably Didn't Have This in Mind
This street-legal jet car — a jet Beetle — has two engines: the production gasoline engine in the front driving the front wheels and the jet engine.
The engine is apparently a GE Model T58-8F. This is a helicopter turboshaft engine that was converted to a jet engine by some internal modifications and a custom tailpipe.
According to its maker, Ron Patrick:
With this project, I was able to use some stuff I learned while getting my fancy engineering degree (I have a PhD in Mechanical Engineering from Stanford University) to design a street-legal jet car without the distraction of how other people have done it in the past — because no one has. I don't know how fast the car will go and probably never will. The car was built to thrill me, not kill me.
And if you didn't think that was crazy enough, check out his next project. A jet powered scooter...... 
More pic's and info of the Beetle and scooter here.... http://www.tomax7.com/comedy/beetlejet.htm
