If you ever in your life thought you were cool with your jump-rope in the driveway (my sister and I used to have "Jump-Rope Olympics"), you have to watch this video.
I have never seen anything like it, and Hallie was entranced the entire time saying "What's that?" to which I responded each time "Jumping!" although that's sort of like seeing a unicorn and just calling it a horse.
I do have to wonder though about the bruises these girls must have come home with when rehearsals were still in the "rough" stages. My goodness!
And if you're not impressed in the first minute, wait for it. IT GETS CRAZY.