How-to: Write a parton-level Monte Carlo event generator
  This article provides an introduction to the principles of particle physics event generators that are based on the Monte Carlo method. Following some preliminaries, instructions on how to build a basic parton-level Monte Carlo event generator for the hard interaction are given through exercises. Indications on how to proceed to full event simulations are given. 
Andreas Papaefstathiou
hep-ph