Rain gutter hydro power generation
 

I'm sure this idea has gone through more than a few of our heads here. Might as well capture some of that water flowing right? Well, this youtuber did a series of videos on the subject showing just how much power can be harnessed (spoiler alert, not much at all) by slapping a hydro generator on a downspout. He actually goes to quite long lengths to get it to work well too. A good series if you have a bit of time.

https://www.youtube.com/watch?v=S6oNxckjEiE

https://www.youtube.com/watch?v=YLb4enCgnP4

https://www.youtube.com/watch?v=vify0k2sHlQ

https://www.youtube.com/watch?v=amu5LJaDUPY

That's a surprisingly well made video!