Former assistant to sculptor Barbara Hepworth, O'Casey's first love is painting. One of the last surviving members of the St Ives School, he focuses on classic abstract subjects - here, in Two Friends, standing nudes are filled out in a satisfying series of ripe ovals, half-moons and circles. At Somerset House, London, until 30 January Photograph: PR
Grayson Perry's teddy bear stars in priapic, angry form in his wool needlepoint Vote Alan Measles for God, at Pallant House Gallery, until 6 March. Photograph: PR
A set of projected slides salvaged from a skip, Sworn transforms her Endless Renovation series in a plaintive meditation on time with voiceover. At Castlefield Gallery until 19 December. Photograph: Malcolm Cochrane
Meticulous renditions of 1950s photographs picked up from a Frankfurt flea market, Gledhill's Doctor Munscheld photo-realist paintings – this is Wohnzimmer mit Blick aufs Esszimmer (Living Room) – have a chilling air of displaced nostalgia. At Castlefield Gallery, until 19 December. Photograph: PR
More obliquely evocative than clearly descriptive, this set of collaged prints – with its empty mirrors and strange contraptions – draws on old catalogue illustrations for barbershop supplies, lab equipment and Army & Navy stores. At Tarpey Gallery, until 4 December. Photograph: PR
Jorn Ebner's graphic digital mischief tends to fluctuate between a utopian heaven and a dystopian hell in an atmosphere of distinctly spaced-out bewilderment – catch LFO Butt Plugs and other computer-enabled scrawls at Vane, until 27 November. Photograph: PR
Lennon showcases her gift for lifting precisely the right thing from the most seemingly arbitrary of sources in her first solo show. But is Prepare to Meet God, pictured, and the rest of her work, proffered as documents of rare cultural import? It's your call. At Ceri Hand Gallery, until 28 November. Photograph: PR
The Glasgow Boys broke out of Scotland's staid fin-de-siècle painting by looking across the Channel: the hot colours of southern France began to creep in, as with exhibition highlight George Henry and EA Hornel's The Druids, pictured. At Royal Academy, Saturday until 23 January. Photograph: Maureen Kinnear
A true Warholian endurance test, Tiravanija's eight-hour film records the working day of an aged Thai man. Still people-friendly, but increasingly political. At Pilar Corrias, until 1 December. Photograph: Cristian Manzutto
