  In this paper we give an overview of Implicit-Explicit Runge-Kutta schemes
applied to hyperbolic systems with stiff relaxation. In particular, we focus on
some recent results on the uniform accuracy for hyperbolic systems with stiff
relaxation [6], and hyperbolic system with diffusive relaxation [7, 5, 4]. In
the latter case, we present an original application to a model problem arising
in Extended Thermodynamics.
