Alysa Murphy, 5, sported a pink helmet with mouse ears while pedaling her bike along East Ninth Avenue in central Denver. Accompanied by her mother and brother — and a baby doll in the pink basket on her handlebars — Alysa made wide zigzags to Dora Moore ECE-8 school. Alysa was one of thousands of children across the state Wednesday to hop on their wheeled steeds — or scooters — to take part in the seventh annual National Bike to School Day. More than 135 schools across Colorado and more than 2,000 schools across the country participated in the event. Ten-year-old David Roberts doesn’t confine his biking to school to the holiday.