Thursday

Boulder Tuesday Thursday Hikers: Join outdoor enthusiasts for a day hike with this leaderless, rule-following drop-in group that breaks into smaller groups and carpools to various trailheads. Drivers are reimbursed for expenses. Bring a lunch, water and snacks, and be prepared for all weather conditions; 9 a.m. Thursday, North Boulder Park, Seventh and Dellwood, Boulder; free; 303-910-9944.

Saturday

Lucky Lyons: Grab some green running gear and participate in a 5K or 10K race on the beautiful paths of Lyons; 9 a.m. Saturday, Lucky Lyons, Bohn Park, Lyons; $35-$45; trailrunner.com/event/lucky-lyons.