Richard Simmons and his glistening legs were on the Late Show with David Letterman last night to talk about fitness and dieting and obese children or whatever. In a dangerously-too-flirty banter, Letterman strayed off topic and openly mocked Simmons' clothes and moist gams, which noticeably ruffled his feathers. But he had a perfect, disarming retort: Scissor kicks!