Thermodynamics laws govern the behavior of macroscopic quantities in equilibrium. However, they do not state anything about the fluctuation of the quantities. In the linear regime outside equilibrium, Onsager has shown a relation between fluctuation and dissipation (the Fluctuation-Dissipation Theorem). However, it is limited to systems in near equilibrium. Recently, it has been shown that time-reversibility of deterministic or stochastic dynamics implies relations between fluctuation and dissipation in systems far from equilibrium, taking the form of intriguing equalities: the fluctuation theorem, the Jarzynski equality, and the Crooks relation. In this talk, I will attempt to explain these relations using simple kinetic models which can be solved analytically. The results will be compared with molecular dynamics simulations.