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]