Whatsonstage.com is kindly assisting London's opera companies to flog some of those seats regular marketing ploys alone cannot shift.
They're offering a handsome discount on Rake's Progress stalls seats at the Royal Opera House on 26 and 28 January and 3 February - £66 (40% off) plus free champagne. Details here.
And there's an outing to Jonathan Miller's new production of The Elixir of Love at ENO on 23 March with a top-price ticket, programme and drink included in the price of £40 (more than 50% off). Details of that one here.