It's not every day South Floridians are given the opportunity to cavort in the manner of a lithe Russian gymnast. Miami, though lovely, is a city about as alien to aerial acrobatics as it is to snow (and by that we mean the real white powder). That is, until the Irish-born Marcus Gaffney and his Flying Trapeze School came to town a few months ago. Perhaps because we city folk have been sheltered from the glee that stems from soaring upside-down some 25 feet in the air, performing twirly, awe-inspiring backflips is probably not on your to-do list. But it can be. And it should be. Not only is it fun, but for those who pride themselves on their testicular capacity (meaning do you have any balls, or not?), it's a must. For $10 for a "try and fly" lesson ($40 for a regular two-hour lesson), you too can inch precariously up a wobbly 23-rung ladder and perch on a ledge the size of a bookshelf high above the green grass of Bayfront Park. Sure it gets the old ticker pumping, but that's nothing compared to the feeling of sheer helplessness that grips your entire being the moment you step into thin air. That's when you realize the only way down is to let go of the bar your sweaty palms are wrapped around, grab your knees, and dismount. Backward.