A lot of folks have bicycles with them

[Motrukdriver]

so this might be something usable for your bike when you don't really wanna ride anywhere but still want some exercise.  Use that expended energy to produce energy.

https://rockthebike.com/roll-up-generator-stand/

Note:  This is a website that sells an interesting bicycle generator/stand combination.

 

[WalkaboutTed]

This was in a thread a while back. It's video of an Olympic bicyclist powering an only 700 watt toaster (they're usually 1200-1500wstts). It'll give you an idea of how effective a bicycle used by Joe Blow would be in powering his system.

 

[Motrukdriver]

I was thinking maybe charging your cell phone.