The annual no-pants subway ride happened Sunday. That's right, fun-loving subway riders everywhere were encouraged by a group called Improv Everywhere to drop trou and ride in their underwear, just for a hoot. In New York alone, an estimated 3,500 braved the cold January weather to do it. Sound weird? Well, in Southern California, merry pranksters gather to moon an Amtrak train once a year. Fun? I guess, but not much of a fashion statement.