If I recall, pricewatch.com introduced the idea of selling airline seats and hotel reservations on-line. The idea was the airline or hotel would gain from selling otherwise vacant seats or renting rooms.
This weekend I ran into three different scenarios where the idea might be applicable. In the Post magazine they ran an article on the Washington Nationals, which included a comment on some empty seats that might be filled by charity. My wife and I went to Wolf Trap Saturday for the NSO concert, again some empty seats. Then Sunday night we went to Kennedy Center for the Suzanne Farrell Ballet (the performance was better than the review led me to expect), also empty seats. I know DC has (or had) a half-price day of performance outlet down on F Street. But why not line up some membership organizations--the Scouts, PTA's, etc. to buy tickets on short notice for real low prices. One thing ballet, classical music, and the Nats share is an interest in building their audience. Maybe they'd attract a return buyer for each 10 tickets they sell.?