  We present a computational scheme based on classical molecular dynamics to
study chaotic billiards in static external magnetic fields. The method allows
to treat arbitrary geometries and several interacting particles. We test the
scheme for rectangular single-particle billiards in magnetic fields and find a
sequence of regularity islands at integer aspect ratios. In the case of two
Coulomb-interacting particles the dynamics is dominated by chaotic behavior.
However, signatures of quasiperiodicity can be identified at weak interactions,
as well as regular trajectories at strong magnetic fields. Our scheme provides
a promising tool to monitor the classical limit of many-electron semiconductor
nanostructures and transport systems up to high magnetic fields.
