Haven't got the stamina to run a marathon? We don't blame you. For those who'd rather exercise their mind muscles, the Serpentine Gallery is throwing its annual two-day marathon festival this weekend. This year's theme is 'miracles', with a focus on rituals, imagination and magical thinking. It kicks off at the Serpentine Sackler Gallery on October 8, and finishes up at Second Home on October 9. There'll be talks on activism, art, anthropology, architecture, literature, music and philosophy, and the line-up includes writers Marie NDiaye and Edna O’Brien, theorists Timothy Morton and Jacqueline Rose, poets Bhanu Kapil and Ruth Padel, as well as performances and presentations from Gilbert & George and Genesis P-Orridge.