Bonobos Undie Run

Take off your pants and hit the streets for a two-mile fun run and after-party. The Bonobos Undie Run is the perfect excuse to do good while raising some hell. All registration fees ($20 per runner) and donations go directly to FCancer, a nonprofit dedicated to "early detection, prevention and providing support to those affected by cancer." Each attendee receives a swag bag and two free drink tickets for the after-party, hosted at the Humboldt Park Boathouse. Running in yourskivvies is encouraged but not required—but hey, if you're registering for an undie run, you might as well go all out.