REI is opening a store in the old Uline Arena in 2016. Ahead of the store opening, they are offering free outdoor classes in bike maintenance, yoga for athletes, knots, and backpacking basics as well as trivia sessions, a run club, and other events. You can see the full schedule and descriptions of classes at http://wundergartendc.com/rei/.
All classes will be held at Wunder Garten, the pop-up beer garden at 150 M Street NE by the NoMa metro. Since the site is a beer garden, you must be 21 to enter or be accompanied by a parent or guardian.
This is a great chance to learn new skills but stick close to the neighborhood!