We normally don't make a habit of posting live videos, even if they are by artists we are feeling, but we're doing it now because Jay rapping over "American Boy" is a big deal. We put Estelle on our summer music cover (did you know that yet? Did we tell you that? JUST KIDDING), and having Jay-Z rap over it is the equivalent of him holding up our magazine and co-signing it in front of like 73 million people. Alternately, you could just look at it as an awesome part of an epic show, or a preview of a remix that might be coming out.