..... so you have probably seen it before. But it is so great that I thought I would post it anyway, just in case anyone is unfamiliar with it. If your computer has speakers, turn them on; but if not, you do still get to play, because it's primarily a visual joy.
How fantastic is that? OK Go, I salute you.
(And just as an aside: I'm not usually a big fan of going to the gym, myself... but I'd be there like a shot if they decided to offer 'Synchronised Treadmill-Skating' classes - it looks like so much fun! So if Duncan Bannatyne or any of his ilk are reading this, you can have that idea for free. Although recompense in the form of discounted entry to my nearest 'STS' session would be much appreciated.)