or maybe car tyres that as they stretch/warp due to the cars weight as the tyre rotates; this way they are powering the cars roof mounted random pedestrian tasering system, without draining any power from the inseat vibrator (for females) or beer cooler (for males).

Boxing Gloves that are powered by punches and store charge for electrocuting the ref when he holds up your winning hand.

the possibilities are endless. Rubber clubs for seal hunting that generate and store enough charge to zap hippies protesting.

Rubber cell phone towers that look like trees and sway in the breeze and charge the leave to zap any seagulls or politicians.

or it could be used for good of some sort..