There's a reason why every basement you entered as a child had one of these gathering dust in the corner. The Bowflex's polymer rod-based weight system allows you to train utilizing dozens of workouts in very small spaces. Rather than trying to cram an entire gym into your basement, you can just pick up one of these and call it a day.

Whether or not people actually used them is a different matter entirely, as we remember seeing the machine most often used to store cardboard boxes or as an unauthorized child's plaything. Good news for aspiring entrepreneurs (and bad news for Bowflex): The patent on that unique "power rod" design expired in 2004, so feel free to try to design your own multi-million dollar workout machine whenever there's spare time.