This past weekend, I went ice skating for the first time in a couple years. I was not as good as I remembered, but I still had a lot of fun. When I was ice skating, a noticed a group of girls who looked like they were on a figure skating team. At one point, one of them went out on the ice. She did some fancy spins, like triple axles and stuff (I don't know very much about figure skating sorry), and I paid particular attention when she would spin. She began her spin with her arms and one of her legs out, and when she brought them in, her rotational velocity increased dramatically. This is a perfect example of the conservation of angular momentum. Angular momentum equals moment of inertia multiplied by angular velocity. When bringing her arms and legs in closer to her body, she decreased her moment of inertia by decreasing her radius (moment of inertia is proportional to mr^2 for any object). Since her initial angular momentum must equal her final angular momentum, the decrease in her moment of inertia causes an increase in her rotational velocity. Watch this cool figure skating video from the 2010 Vancouver Olympics to see for yourself.