CODE
llSitTarget( <0,0,1>, ZERO_ROTATION );
llSetCameraAtOffset( <0.4,0,0> );
When you sit on it and hit ESC (to snap your camera to the sit target point) you will be looking straight down at the ground. Now mess about with your menus (drag one around the screen or something) and soon you'll see a little pause. The longer you wait, the longer the pauses will become and the less time you'll have between them.
Meanwhile, the client's virtual memory usage will start to climb, doubling or tripling. Sit there long enough and the client will freeze up solid.
If you get off the prim before it gets too bad, you can move around as normal, but whatever pause rate you had achieved will STILL be with you until you quit and restart.
This is true for both the Mac and PC versions. I have bug reported it and given Colin a copy of the object, but no word yet.