In the AdS/CFT correspondence, the thermalization of strongly coupled field theories with a gravity dual can be assessed through probes which have a simple geometric interpretation in the bulk space-time. In the saddle-point approximation, the calculation of two-point functions, Wilson loops and entanglement entropy reduces to the computation of geodesics, minimal surfaces and minimal volumes in the asymptotically AdS space. I will discuss the scale-dependence of these probes in the thermalization of strongly coupled field theories in d=2,3,4 perturbed by a sudden injection of energy. The expectation values are obtained holographically in the dual gravitational setup of an infalling shell of null dust in AdS.