At first glance, I was like "OH MY GOD HOW HAVEN'T PEOPLE THOUGHT OF THIS ALREADY?!" I mean seriously, it's a simple idea. Can opener to the top of a beer can, and you have instant cups for pong or whatever other game you can come up with.
But then I actually thought about it for a second. Actually, this would probably change the game in a bad way. Can you picture yourself taking a big ol' gulp of beer and accidentally slicing half your face off with the sharp edge of a beer can? Even the idea of trying to pick a pong ball out of the can, slicing your fingers up and getting all that blood into the beer. Who doesn't love the idea of drinking the blood of a complete stranger you met in the basement of some dingy house?
So. cool thought. But maybe not the greatest idea after all.