The sequence of ideas in a re-discovery of the Colombeau algebras
  This is a gentle introduction to Colombeau nonlinear generalized functions, a generalization of the concept of distributions such that distributions can freely be multiplied. It is intended to physicists and applied mathematicians who prefer a `step-by-step approach' to a `top-down indoctrination.'   No particular prerequisite knowledge is necessary -- and in less than one hour you should know everything you need to know and were afraid to ask about Colombeau algebras and their applications in physics...   A selected bibliography is appended, giving examples of applications to partial differential and wave equations, electrodynamics, hydrodynamics, general relativity, and quantum field theory. 
Andre Gsponer