In section 1.1 of Stormbringer ("What is Roleplaying?"), Ken St Andre includes a very succinct explanation of what a RPG (or FRP game, in his usage) is and what its play consists of, part of which follows:
The FRP game's use of dice makes them partially a game of chance, unlike chess or other mathematically-based games that are purely games of skill. However, skill is definitely involved in the play of an FRP. Players need to develop skill in problem-solving, communication with others, and the ability to make rapid decisions, and when those skills are combined with luck and vicarious adventure, FRP games become far more interesting than any amusement based on only one of these factors.The italics are mine, because I consider them pretty important and key facets of the style of play I most enjoy. These are topics I'll be returning to at a later date, but I was trying to remember this quote earlier today when I wrote my piece on random character generation. Now it's here and I can refer to it later, as needed.