This is really cool. I've oft wanted to do make kaleidoscopes with the kid makers and tinkerers that I work with sometimes, but I've never seen a project that seemed quite manageable enough to do with nine year olds. But this one definitely is, and it's all reuse, to boot! Find yourself an old cd case, a yogurt lid, and a few other odds and ends, and you're in business. Found at makezine.com.
3D Printed DSLR SLider! For less than 20$
10 hours ago