The Hövding, developed by Anna Haupt and Terese Alstin, is an inflatable helmet. It's designed to protect a bicyclist's head without mussing his/her hair:
Hövding is a discreet collar that the cyclist is wearing around his neck. The collar contains a folded airbag which is visible only at a collision. The airbag is designed as a hood that in case of an accident will enclose and protect the cyclist’s head. Release mechanism is controlled by sensors that register abnormal movements of the rider in an accident.
At the link, you can watch a video of the helmet inflating during crash tests.
Link via Popular Science | Photo: Hövding
Previously: An Airbag for Equestrians