Yesterday Inhabitat reminded us about that River Gym idea that was, er, floated back in 2005 as part of New York Magazine's contest for forward-thinking gym concepts. Dr. Mitchell Joachim and Douglas Joachim's idea for a floating gym is premised on "transforming wasted human mechanical energy into a useful kinetic gymnasium." Their eco-friendly gym would harness the energy usually lost during New Yorkers' workouts and use it to power boats back and forth across the Hudson and East Rivers. more ›