Long exposure of an amusement ride called the Inverter
This was with a Canon 20D, using a Neutral Density filter to actually reduce the light.
I shot a number of these while trying to get the timing correct, ending up with partial rotations or someone stopping in front of my tripod setup halfway through a 30 second exposure. The nice thing about digital is you can see immediately if you have the shot.
The ride only does 2 full revolutions each time they run it. It swings from side to side, like a pendulum gaining momentum, then it rotates to the top, stays for about 2 seconds , does 2 full revolutions, then returns to the partial rotation. Once it is done, then unload the 24 people and reload.
Canon 20D, EF-S 17-55 f/2.8 IS USM, ISO 100, f/22, at 10 seconds.