RCA Secret 2011

Annual exhibition and sale of around 2,500 specially commissioned, postcard-sized works of art. The identities of the artists, a mix of young students and famous names (artists who have donated work in the past include Peter Blake, Tracey Emin, Grayson Perry, Nick Park, Ron Arad and Yoko Ono), are not revealed until the end of the show, when visitors who have registered in advance can buy mystery postcards for £45 each. The exhibition runs Nov 18 to 25 and the sale takes place Nov 26.