Yoko Ono invites Berliners to participate in this exhibition inspired by a poisoned apple – Das Gift translates as "the poison" – at Haunch of Venison (Sept 10-Nov 13). On the first floor, visitors can leave behind stories or images they associate with violence, or investigate “The Hole” – a shattered pane of glass that claims to put viewers in the dual perspective of gunman and victim. Frowns are forbidden on the second floor: “Smile Room“ records visitors’ smiles and beams them onto a video loop. Very Yoko...