"Flip lights" — turn them upside down, and they’re off. Turn them back up, and they’re on. Here's an easy soldering project that's really fun to use. New from Make: Volume 41.
Project animations from the rear of your bicycle using a Raspberry Pi and open-source software. The framerate of the animation depends on the speed you are moving at.
Build a Robotic Balloon Muscle from the book "Making Simple Robots: Exploring Cutting-Edge Robotics with Everyday Stuff" by Kathy Ceceri, published by Maker Media.