Sunday matinee improvised music monthly: Winter Solstice Special with around 40 musicians playing short sets in different combinations including Dominic Lash, Mark Wastell, Paul Pignon, Gabriele Meirano, Jamie Coleman, Ntshuks Bonga, Steve Beresford, Faradena Afifi and more to be announced (21 December, noon), Olga Ksendzovska & Sylvia Hallett + Martin Lau & Jo-Anne Cox + John Butcher & Benedict Taylor (18 January), Simian Carbuncle + Sam Bailey + TBC (15 February). London The Vortex, 2pm unless otherwise noted, £12–£8.