This video has been around for a few months, but I just came across it and it's astounding. Check out this Brazilian teen's scratch-built model backhoe. Using plastic syringes and silicon tubing, he's created a miniature hydraulic system that functions the same exact way as the mechanism inside a real excavator. This kid is sharp.
I especially like watching this junior engineer's finesse at the controls. There are no jerky movements—every maneuver is fluid and smooth. If you watch closely, you can see him overlap the four control pistons, ensuring a smooth, seamless transition between vertical and horizontal motions.
There are a bunch of great instructions out there that show you how you can build a syringe-based hydraulic system to power creations of your own. Toys are way more interesting when you make them yourself. [Catalin Sogor via BoingBoing]