  The path integral formalism gives a very illustrative and intuitive
understanding of quantum mechanics but due to its difficult sum over phases one
usually prefers Schr\"odinger's approach. We will show that it is possible to
calculate simple quantum phenomena by performing Feynman's sum over all paths
staying entirely in real time. Once the propagator is obtained it is
particularly easy to get the energy spectrum or the evolution of any
wavefunction.
