The infamous burpee! Hate 'em or love 'em, they make for great cardio & are a full body strength movement that can be done any time any place. Start in push up position and lower to the ground - it isn't necessary to do a full push up here. Straighten arms to return to push up position, and hop your feet to the outsides of your hands. Make sure knees are in line with ankles. Jump into the air, shooting hands up overhead. Return hands to the ground and hop feet back into push up position. Repeat as quickly as can be controlled.