  We discuss the lattice formulation of gauge theories with fermions in
arbitrary representations of the color group, and present in detail the
implementation of the HMC/RHMC algorithm for simulating dynamical fermions. We
discuss the validation of the implementation through an extensive set of tests,
and the stability of simulations by monitoring the distribution of the lowest
eigenvalue of the Wilson-Dirac operator. Working with two flavors of Wilson
fermions in the adjoint representation, benchmark results for realistic lattice
simulations are presented. Runs are performed on different lattice sizes
ranging from 4^3x8 to 24^3x64 sites. For the two smallest lattices we also
report the measured values of benchmark mesonic observables. These results can
be used as a baseline for rapid cross-checks of simulations in higher
representations. The results presented here are the first steps towards more
extensive investigations with controlled systematic errors, aiming at a
detailed understanding of the phase structure of these theories, and of their
viability as candidates for strong dynamics beyond the Standard model.
