Many thanks to reader Vecchio John for pointing out that booking opened this morning for La Scala's June 2013 Ring cycle.
There are two cycles, beginning 17 June and 24 June. Tickets range from €435 (top balcony) to €1,200 (best stalls), and there were plenty left in all price ranges at the time of writing. They are currently being sold only as 'packages'. These include all four operas and various extras like free drinks and theatre tours. If you're thinking of buying the cheapest tickets, bear in mind that the balcony is a looong way up.
Although Guy Cassiers' production has been slated, there are musical compensations. Casting includes Rene Pape and Michael Volle as Wotan, Irene Theorin as Brünnhilde and Waltraud Meier as Sieglinde - and of course Daniel Barenboim conducts.
Warning - the purchase process is a bit 'Italian', and you need to enter your personal details before you can select seats. If you pay by Visa or Mastercard, you will need to pre-register on a completely different site. And there is a commission charge.

