Possibly the best lighting system in the world for the bike-to-work set, the spoke-mounted Revolights cast light as you ride to provide 360 degrees of visibility and reduce your risk of being T-boned. Each narrow ring has 24 LEDs, eight of which are illuminated at once to provide a clear, consistent 280 lumens per wheel. When the wheels spin, the LEDs cast bright arcs of light, and an easy-to-detach rechargeable lithium-ion battery provides four hours of power. An accelerometer and set of tiny magnets on each component keeps the light show in sync, regardless of how fast or slow you pedal. The only downside? The system is time-consuming and a bit frustrating to install, as it attaches via an Erector Set-like collection of small parts. But there's one other bonus: If you lock your wheels, the lights are virtually theft-proof. [$250; revolights.com]