Most of the interesting things that we observe around us are flowing, growing, evolving, and are thus out of equilibrium. Contrary to equilibrium systems for which the state of the system can be predicted knowing only the Hamiltonian, the vast diversity of nonequilibrium systems requires to study different types of dynamics with different tools. In this course, we will cover some of this diversity, limiting ourselves to classical systems. We will start from systems « close to equilibrium » for which transport properties can be recast as equilibrium correlation functions using Green-Kubo relations and systems that undergo coarsening following a rapid change in external parameters. We will then cover various models that allow us to grasp different phenomena like traffic jams, condensation, epidemic spreading, interface growth, flocking and motility-induced phase separation.