Some kids get excited when they get the Christmas present they've always wanted. Some kids get really excited when they get that present, and this young boy is one of them.
This young lad (who - judging by the site this originally came from - comes from the Netherlands, I'm hazarding an Uneducated American Guess) received an Xbox 360 for Christmas, and had apparently been waiting for it for quite some time, judging by his reaction. There is screaming. There is running in air while lying on the ground. And most importantly, there it is - captured on the Internet forever. Well, that's assuming it's not staged, which is always a possibility.
I'm not sure which is funnier, the knowledge that this kid will be one of your Modern Warfare 2 teammates soon enough, or wondering how he'll react if the thing ever Red Rings on him.