On 14 and 15 October, Valery Gergiev's Mariinsky Orchestra will join the CBSO, two choirs, ten timpanists, four brass bands, a donkey and a magic trombone to perform Berlioz's Grande Messe des Morts in Birmingham's Symphony Hall.
With nearly 400 musicians and singers required, it's rarely performed in the UK. But concertgoers will be able to repeat the experience at leisure by taking home a live recording of the performance on CD immediately afterwards.
Although this has been done before by rock bands (I have a treasured White Stripes effort from Alexandra Palace), I think it might be the first time a classical orchestra have attempted it in the UK. Way to prop up the dying CD market!