The Washington Nationals 2017 Winterfest is Dec. 16 and 17, 11:30 a.m. to 4 p.m., at Washington Convention Center, 801 Mt. Vernon Pl. NW. Attend clinics with Nationals players and coaches. Watch a Home Run Derby featuring the Nationals mascots. Make a snow fort. Participate in the steal home challenge and take batting practice. Hear a winter or baseball-themed story read by a Nationals player. Participate in the Kids Press Conferences. Sign up for 2018 season Jr. Nats Kids Club memberships. Ride down a giant slide reminiscent of a sledding hill; and “Video Pitch,” where fans can give virtual batters their best pitch. Tickets start at $25 for kids; $35 for adults. nationals.com/winterfest.