Excellent podcast with founding member of Upright Citizens Brigade Matt Besser. Each episode features fantastic improvisers who break off into scenes as they discuss miscellaneous topics. Dirty humor is not uncommon, fyi.
There are many many definitions of a game, most of which differ only subtly. Some are dependent on the definition of play, but that's a whole other discussion. Maybe I should have written about that first, oh well. Anyways, here are a few ways to define a game, accompanied by thoughts:
Katie Salen and Eric Zimmerman define a game as a "system in which players engage in an artificial conflict, defined by rules, that results in a quantifiable outcome".
Conflict, rules, and a goal are the driving factors in about all definitions I've read. I think the unique part of this one is "quantifiable outcome" which would mean a goal. But saying "outcome" instead of goal, seems like you could get there without necessarily meaning to. I guess technically, there are games (like the card game War) you could win by just following the rules with no ambition.