American football is like Rugby but slower, with far too many (commercial) breaks, & a load of armour that Real Men (OK, Real Stupid, or Real Psychopathic Men, if we're talking about Rugby players...) don't need. It comes in two flavours, AFL & NFL, but since no-one outside of the US understands what the hell is going, no-one outside of the US can even be sure whether they're playing by the same rules...
(Now if that doesn't start a trans-atlantic flame war... That sinbin, he's a troublemaker, I'm tellin' yez...)