YouTuber luisengineering likes to ramp up the power of ordinary household devices. In the past, he's modified a robot vacuum so that can move up to 37 MPH and adapted a Nerf Blaster to fire tampons.
In a similarly practical vein, he wants to deal with a roommate problem. His video is in German, but I gather that our hero lives with three other men and all four like to use electric toothbrushes. There aren't enough electrical outlets in the bathroom to keep all four toothbrushes juiced, so he has built an off-grid solution.
Luisengineering bought a 2-cyclinder 4-stroke gasoline engine with a 7 cc displacement. After designing and 3D printing new parts, he was able to drive this power to his toothbrush.
Hearing protection is advised while using this powerful and loud tool.
-via Hack a Day