Ever wish you could get the same kind of challenge while swimming against the current in a public pool but are unable to do so? The Pool Treadmill is one device that turns any swimming pool into a bona fide exercise machine, making your body ache in parts you never knew you had after a vigorous session. All you need to do is hook the trailer and electric motor up to the side of the pool, turn it on, and see it generate a downstream current of up to 6 mph. It is powered by rechargeable batteries, so you can just bring it over to your friend’s house at Beverly Hills if your backyard has no space for a pool. The $3,999.95 price would scare most people away though. At least with the Pool Treadmill you no longer have to worry about dashing your head against some rocks while swimming for your life.