  We describe a framework to develop, implement and validate any perturbative
Lagrangian-based particle physics model for further theoretical,
phenomenological and experimental studies. The starting point is FeynRules, a
Mathematica package that allows to generate Feynman rules for any Lagrangian
and then, through dedicated interfaces, automatically pass the corresponding
relevant information to any supported Monte Carlo event generator. We prove the
power, robustness and flexibility of this approach by presenting a few examples
of new physics models (the Hidden Abelian Higgs Model, the general
Two-Higgs-Doublet Model, the most general Minimal Supersymmetric Standard
Model, the Minimal Higgsless Model, Universal and Large Extra Dimensions, and
QCD-inspired effective Lagrangians) and their implementation/validation in
FeynArts/FormCalc, CalcHep, MadGraph/MadEvent, and Sherpa.
