Every once in a while, I discover a new mobile device charger that is really practical and energy-efficient, like the Solio Magnesium Solar Charger. Today I found two devices that charge using another renewable energy source: kinetic energy.

The first is the Orange Dance Charge. This is an armband that you can connect your mobile device to, and then shake it up (preferably while dancing) for a charge. It has the same kinetic energy charger that you see in those “never need winding” watches. So if your cellular phone needs a charge, just dance around like Martin Short back when he was playing Ed Grimley on Saturday Night Live.

The second is a charger that sounds like a cheap joke, but it is real proposal. Apparently, a woman named Adrienne So has proposed a way to harness the power of breasts. That’s right, with a little nanowire fabric in a bra, you can actually capture the energy produced by the up and down movement of the (insert any synonym for “breasts” here). I’m going to justly resist any comment that I could make after introducing a gadget like this.

Yes, that last proposal does sound like a joke, but it is no joke that we often go through the day with a lot of untapped kinetic energy that we could really use for our mobile devices. Unfortunately, both of these ideas are in the proposal stage at this point.

Source 1 and Source 2