Throughout their season, the Washington Nationals baseball team in conjunction with the Washington Post offer a sweet deal called the "5 Series" whereby one can purchase $5 tickets for nosebleed section seats through the team's official website or line up in front of the will-call booth about 2 hours prior to game time. In addition, prior to the first pitch of each game, one can get $5 beers at the Miller Lite Scoreboard Walk Bar. Enjoying a beautiful yet humid Friday evening as the Nationals won. Look for the advertisement in the Sports section of the Washington Post.
Whether you are from DC or travelling from abroad, I recommend an afternoon at the ball park. Go to stub hub to find great ticket prices. Also, there is a Shake Shack at the Nationals Stadium (in case you need more incentives).