The Community episode about D&D is a very accessible introduction to the hobby. It provides a few good role-models and some bad ones, and really communicates the feel of the game to a beginner. I don't advocate their particular play style, but it serves as enough of an introduction to build off of. It's amazing how many unspoken assumptions are outlined in the episode which help later when the beginner sits down at the table.
As far as teaching the game, it's easy if the player wants to learn. There are many good guides for introducing players to the game though, and I'm tired, so I'll leave it at that. Good luck.