No Bike Lock? Use Your Handlebars
There have been all kinds of inventions and concepts aimed at making locking your bike easier and more intuitive. The bike belt is a pretty sweet way to carry your lock around. But even that could foreseeably be uncomfortable and irritating. So why not figure out a way to integrate the lock into a place where you won't notice it at all--the bike itself.
A design by Bach Nguyen, the Handlebar Bike Lock is exactly what it sounds like. Instead of carrying a separate lock, all you have to do is push the release buttons on the handlebars, pull the handlebars out, wrap them around a pole, fence or bike rack, and close the lock.
As tends to happen with concepts, the hardware behind the Handlebar Bike Lock isn't exactly clear. I assume those are some rugged steel cables that are retracted by some type of winding mechanism inside the bike's stem. But that's just a guess, because there's no real explanation.
Cable locks aren't the most effective type of lock, but they're sure better than nothing at all. And with the Handlebar Lock, you're sure to have a lock with you at all times. Until you get a new bike.