May is national bike month, so get two-wheeling, but play it safe: always wear a helmet. While biking helmets never feel stylish, the Propero II ($110) from Specialized is so comfortable and lightweight, you forget you have it on. Designed for the female head, the shape and interior cushioning make this helmet incredibly comfortable and ensure tight but pleasant fit. It even has an opening in the back to accommodate a ponytail. The larger vents keep my well-protected head cool when climbing on the sunniest of days.