The experimental observation of driven Brownian motion and an analogous electric circuit confirms that the thermodynamic entropy production can be measured using the probabilities of the paths and their time reversal, i.e., from time asymmetry in temporal disorder. In this way, irreversibility is observed down to the nanometric scale in the position of the driven Brownian particle and a few thousand electron charges in the driven electric circuit. In addition, underdamped and overdamped driven Langevin processes are shown to obey the fluctuation relation and its consequences are discussed. The following examples are considered: a particle moving in a periodic potential and driven by an external force, a driven noisy pendulum, a driven noisy Josephson tunneling junction, the stochastic motion of a charged particle in electric and magnetic fields, and heat transport driven by thermal reservoirs.