The Hayward Gallery in the Southbank Centre often has free exhibitions - check the website for details.
UG: Waterloo 0.36km
UG: Embankment 0.4km
OG: London Waterloo 0.49km
Mon 12-6pm, Tue,Wed,Sat,Sun 10am-6pm, Thu, Fri 10am-8pm.
Always check details regarding opening hours, accessibility and pricing before travelling.