The Garmin Head-Up Display is a $150 gadget that connects to your mobile phone via Bluetooth and projects navigation information onto your windshield. I want one - I use my iPhone for navigation and I don't like picking it up and looking at the display while I drive.
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