We all know you can find a discount code for anything at ENO if you look hard enough, though usually they get other organisations to spread the news. This time they're doing the dirty work themselves, via a mailing to selected customers (of which I was not one, so thanks to reader Cat for forwarding).
For half-price tickets for the last few Magic Flute shows - Nov 28, 30 & Dec 3, 5 & 7 - book online using the promo code 50FLUTES. It's valid for all price bands except the top one (£110/£125).
I can't recommend the show to anyone except diehard McBurney/Complicite fans. If you're tempted though, I would strongly suggest going for the most central and forward seats you can find, otherwise you'll miss some bits.