I have one question before I lay down my argument. I think we are all in agreement that movies are a form of art. If that is so, can you broadly call ALL movies art? Is Dumb and Dumber as much art as Citizen Kane? I'm not sure, but I can tell you this; I know many people that would much rather watch Dumb and Dumber than Citizen Kane. Does that say anything about the artistic value of either, or are both movies still art and its just a matter of taste and preference. Is a scribble crayon drawing done by my toddler niece any less art than the Mona Lisa. That crayon drawing has a whole lot more meaning to my niece than the Mona Lisa does. My point is that art can be very hard to define sometimes and open perspective should always be considered when asking the question, "IS THIS ART?"
That being said, this is the way I see it. (I stress that I am no authority on the subject except that I enjoy both movies and video games.) If movies are art, than video games have to be art. Because they share ALL of the same elements: Characters, story, setting, antagonists, protagonists, mythos, pathos, ethos, symbolism, etc. It's that simple. If you didn't know video games had all these elements, then you haven't been playing close attention to video games. If at least some movies are art, than at least some video games are art.
That is my argument. However, that best arguments for video games being art that I have ever encountered have been voiced in the following two videos:
http://www.escapistmagazine.com/videos/ … hing-Lives
http://www.escapistmagazine.com/videos/ … -Mechanics