Need A Microscope? Got Fifty Cents? No Joke!
 

I was blown away by this, and am already signed up to get one:Foldscope: Origami based print and fold paper-microscope

Ah, and origami is so much fun! We had a microscope when the kids were little and I made up quite a few slides so that they could 'take a closer look' at the world around them. I used it, too, to keep track of the health of my goldfish pond. :)