Fear not, you won't have to run in your birthday suit. Go for a 5K walk/run at City Park or take a loop through the Denver Zoo to benefit Underwearness, a national organization with the cause of providing underprivileged children with new underwear. Registration costs include zoo entry to the private event, t-shirt, two drink tickets, and goodie bag. Fri 6:30 p.m.

Visit http://www.underwearness.org.