This waterless swimming device, as seen on the show American Inventor, is one of the most hilariously terrible things we've seen in a while. It takes all the grace, fun, and fluidity of swimming and makes an awkward, painful looking exercise out of it. Just look at the guy's face after he's done using it!
Here's a tip: if you look like you just had a stroke after using your invention, it sucks.
American Inventor [ABC]