We give an overview of important results for non-atomic congestion games in their traditional form along with self-contained and short proofs and then present new results and challenges for an extended model, which we call
consumption-relevance congestion games
. We introduce the consumption-relevance congestion game first and show that all other models are special cases of it. Our focus is on the price of anarchy, computation of equilibria, and experimental studies. Further interesting aspects are summarized at the end of this article.