Exercise Powered Electronics
(good for the future)

(Hand-powered mechanism for computers and game consoles -
via rowing machine in this case)

https://yewtu.be/watch?v=qhejwuDLr24

Good for adults and children.

I have actually been part of a bike-powered home cinema which needed:
- 2 static bikes
- Small projector
- Inverter
- Regulator
- Battery and maybe a few other bits I forget

For hours audience took turns to cycle (or just me with smile on my face)

If you have experience with this let me know!