The Chicago Polar Bear Club's annual New Year's Day swim is a tradition (and time-tested hangover cure) that dates back to at least the '40s. Each year, hundreds of half-drunk, half-asleep "swimmers" congregate on North Avenue Beach to brave the unbearable temperatures for an icy dip into Lake Michigan. After shedding coats, scarves, and clothing — and leaving Irish coffees in the hands of more sane spectators — brave souls attempt a 30-second, full-immersion plunge into the frigid water. Many don't make it in deeper than their ankles, but just stripping to your swimsuit in 20-degree weather (no wetsuits, no nudity, and no whining allowed) is enough bragging rights to last a lifetime, or at least until next year.