How to make attractive the teaching of relativistic electrodynamics?

Real experiments are sometimes missing or highly expensive to implement when teaching the different movements of charged particles in relativistic electrodynamics. A fast, accurate and easy to use Matlab code dealing with this problem is presented. It is used for computing the trajectories of such particles in an electromagnetic field and for illustrating some effects of relativity that cannot be brought to the attention of students without the aid of numerical simulations.