Last night I went to Crash Space, a hackerspace in Los Angeles, to see the cool things that its members have been working on. One of my favorite projects was Naim Busek's "Bike Luminance," a signal light that you can attach to a bike helmet so drivers can see where you are and where you plan to go. When you tilt your head back, the bright LED light strips blink red. When you tilt forward they turn green. When you tilt your head to one side or the other, the light strips become turn signals.
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects