Check out the Hula Chair. Basically, you plant your feet flat in front of you, press the button, and start moving your hips and core in a circular motion.
The makers say it will improve your balance and coordination as it gently aligns your spine and improves blood circulation. You'll love how it feels as it works out your abs and mid-section. They say it is a great way to warm up for any activity.
Hmm, you could spend $199.95 on this ("operators are standing by 24 hours a day"), or buy 3 regular hula hoops from Wham-o for just $14.95. Then you can hula hoop with some friends, and for only $5 each.