Confusingly, there are two "No Pants Days". One is held on the last day of May - the other, at some point in January, as decided by infamous pranksters "Improv Everywhere".
Yesterday was 2012's "No Pants Subway Ride" day, an event that sees commuters all over the world whipping off their trousers - that's right, trousers - just for the sake of whipping off their trousers.
Making thousands of fellow commuters laugh / cry / feel remarkably uncomfortable, it's attention-seeking on an industrial scale - but as attention-seeking on an industrial scale goes, it's a pretty funny one.
When the joke fails to make anyone chuckle any more is a matter of opinion, but the chance of seeing people look uncomfortable when confronted with a pair of human thighs is still one to be relished.
You can find a video of the "Improv Everywhere" crew and their followers doing their thing above, and for a picture gallery - including British leg-barers - get clicking below.
Oh, and in case you were wondering, the other "No Pants Day" is on the first Friday of May - which is 4 May this year. Write that down in your copybooks... now.