Monte Carlo Simulations
  Monte Carlo computer simulations are virtually the only way to analyze the thermodynamic behavior of a system in a precise way. However, the various existing methods exhibit extreme differences in their efficiency, depending on model details and relevant questions. The original standard method, Metropolis Monte Carlo, which provides only reliable statistical information at a given (not too low) temperature has meanwhile been replaced by more sophisticated methods which are typically far more efficient (the differences in time scales can be compared with the age of the universe). However, none of the methods yields automatically accurate results, i.e., a system-specific adaptation and control is always needed. Thus, as in any good experiment, the most important part of the data analysis is statistical error estimation. 
Michael Bachmann
cond-mat.stat-mech physics.comp-ph