From flares, to magnetohydrodynamic and acoustic waves, to the 22-year magnetic cycle and beyond, the Sun exhibits variations on a wide range of timescales. Modern observations from space and ground-based instruments reveal these phenomena with unprecedented spatial, spectral, and temporal resolutions. Such observations have driven forward rapid advancements in the theoretical and numerical modelling of key physical processes and their seismological application. This session will bring together members of the solar community to discuss these oscillations and instabilities, and the way they interconnect and influence one another.