Invented by the man who created Rollerblades, Scott Olson, the Rowbike is a rowing machine with wheels. According to the Rowbike site it burns approximately 50% more calories than ordinary biking and twice the cardiovascular benefits. The Rowbike comes in 5 different versions. One of the versions, the 420 crewzer, is a 4 wheeled model perfect for those who still have training wheels on their bikes. Price:$599-$1999
Watch the videos to see how it works.