A dancing white mare.

As many of my fellow country bumpkins know, I spent most of my childhood rampaging around on horseback in the hills behind my parents' house. When I was a kid my family didn't travel or spend money on cars or camps or frilly dresses for school dances... instead, we kept a couple of horses--a mischievous black Arabian with rubbery lips and a knack for unlocking gates, and a small, spirited, flaming red Quarter Horse, who we rescued from neglect and loved me to pieces.
In general I liked taking my horse (the red one) apple-picking and running wild in the woods, paying as little attention to stuffy riding conventions as possible. We couldn't be bothered to saddle up or "look pretty"--bareback, and with both our manes and tails askew, we stampeded our way up trails and down ravines and had an excellent time together. She was an awesome companion.

Anyway, the way that my horse and I operated was in stark contrast to what follows in this YouTube clip (and I think my horse much preferred it that way, to be honest). Typically I can't agree with people who try to make their horses perform unnaturally, so I don't advocate stuff like dressage (shown in the clip) or show jumping... but nevertheless, I can't resist posting this. (You'll need audio to appreciate it fully, and try to watch at least a few minutes, because she doesn't really get going until the YouTube timer reads 4:50.) The horse is obviously dancing to the music on the loudspeakers and seems to be getting a real kick out of it. Look at her keeping time with her hooves, it's insane... and watch what she's doing with her tail (particularly later on in the video); she's like a sorority girl flipping her hair. Pretty funny.

Anyone who says that animals aren't sentient beings obviously hasn't seen anything like this. No human dances this well.