We've all been there. You climb into bed, you turn off the nightstand lamp, and you think "Did I close the garage door?" Save yourself the midnight trip to check on the garage with this ingenious hack.
Instructables user kcj2010 hated peeling himself out of bed to double check on the garage door and hated waking up in the morning realising he'd left it open even more. His solution was to wire a sensor to his garage door and place an indicator light hidden in the light fixture of the master bedroom.
When the garage is open, a small red LED shines on the light fixture and gives an immediate and highly visible indicator that the garage door is open. No light? The garage is closed. Seems like an idea that could be applied to any swinging or sliding door that causes you concern. Check out the Instructable for the parts list and wiring diagram. Sound off in the comments if you've undertaken a novel hack of your own to solve a problem around the house.