My uncle forwarded a link to this to me and I had to share it with you. The tune is catchy (though nonsense), but that is not why you should watch it. The Ross Sisters sound a lot like the Andrews Sisters, but I bet the Andrews Sisters didn't have moves like this. My uncle recommended that I try using some of these moves in my dance classes, but for some reason I don't see that happening :-)
Some people are double jointed, some people have rubbery arms and legs, some people have great balance, I think these girls have all three... make sure you watch over a minute, that's where it starts to get crazy!