Established in New York City in 2002 by a group known as Improv Everywhere, January 13th marks the annual No Pants To Work Day. Participants in over 50 countries, including Australia coordinate via social media and ride the train to work in their underpants acting as though what they are doing is totally normal. While silly, riding public transport without pants is legal in Australia and the confusion on the faces of onlookers is priceless.
Observe the tradition of the Eagle Rock.
This tradition which has its origins at the University of Queensland in the 1980s. When the Daddy Cool song "Eagle Rock" plays in a pub or club patrons of the establishment (particularly young male students) drop their trousers for the duration of the song. This ludicrous display tends to mystify non-locals but it's harmless fun.
The practice of swimming in near-freezing water is popular in just about every part of the world that has both a truly cold winters and a large enough body of water to swim in. In Vancouver, Canada the Polar Bear Swim Club has indulged in this madness since 1920. South Queensferry in Scotland hosts the annual "Loony Dook" each New Year's Day. Members of the team at Mawson Research Station in Antarctica have even been known to create a makeshift swimming pool by cutting a hole in the ice with a chainsaw and hop into it (pantsless of course) for a quick, agonising dip. Why? I suppose it proves how tough you are or something.
The Ancient Greeks, who established many of the foundations of Western thought, were not into the wearing of pants, favouring instead a simple tunic known as a chiton with a cloak worn over the top. Who knows, maybe there is a connection between clear thinking and letting the breeze get to your nethers. It might be fun to find out.