  Computational gas dynamics has become a prominent research field both in
astrophysics and cosmology. In the first part of this review we intend to
briefly describe several of the numerical methods used in this field, discuss
their range of application and present strategies for converting
conditionally-stable numerical methods into unconditionally-stable solution
procedures. The underlying aim of the conversion is to enhance the robustness
and unification of numerical methods and subsequently enlarge their range of
applications considerably. In the second part Fabian Heitsch presents and
discusses the implementation of a time-explicit MHD Boltzmann solver.
