The Kennedy Center has a free discount/giveaway ticket program for people under the age of 30 called MyTix.
You can either buy discounted tickets on a first come first serve basis or enter their free ticket giveaways.
They are currently holding a giveaway for The Elixir of Love Opera for March 20, 2014 at 7:30 pm.
Enter to win by February 26, 2014 11:59pm.
I was able to get 2 second row orchestra tickets to see the Moby Dick Opera for tonight for $30 bucks each! :)