Mostly entertainment. On occasion, a game comes along that can be considered a work or art.
But just because a game isn't art doesn't mean it can't be fun, nor that it can't be good. Say... Call of Duty. The games, in my opinion, are fairly good. I have fun with them. But they are still pretty much pieces of entertainment, made with the intent to sell as much as possible. But when a studio takes their time to create a world with a rich backstory, when they make a game that seems like it has the intent to tell a story, or when they make a world that is a delight to explore, where you can get lost and forget about the main storyline, I believe that can be considered art.
It's like films, or music. There are works of art. And then there's the summer flicks and the pop singers. They're not necessarily bad, simply entertainment, with low artistic value, and there's nothing wrong with enjoying them for what they are.