One of the most fundamental discoveries in physics and astrophysics was made with the discovery of pulsars. Ever since, pulsars – and later in particular binary and millisecond pulsars – have been studied as extreme end-states of stellar evolution, as super-dense objects, as radio and high-energy sources, as probes for the interstellar medium, and as super-precise clocks for fundamental experiments in gravitational physics. This article reviews some of the exciting applications of pulsar physics and the amazing prospects that are promised by the advent of the Square-Kilometre-Array (SKA).