There's a site that offers all sorts of football invitations, in the States. I can't quite imagine why you'd need to invite people to football. There seems to be more than enough people go to the games as it is without inviting more.
But plainly the owners of this site don't think that way, and you can see all sorts of examples of invitations you could give out to friends, relatives, and the uninitiated - the unconverted, you might say. (The idea has a sort of evangelical quality about it.)
Admittedly, the invitations don't have to be to an actual game, but to a party, or a barbeque with a football theme, or even to watch the football in the comfort of your home, surrounded by mates and beer.
American football is a neverending mystery to anyone outside the States; it seems as though there must be some logic to it, and some plan (the movies always give us that impression without actually telling us what they're doing) but at the end of the day, watching this game is like watching a couple of herds of elephants running at each other after bowing their tusks to the ground. And the injury rate is pretty much as high as it would be if elephants were playing.
Still rugby isn't different in terms of obscurities (more obscure than ever with all the changes that have been made) and the injury rate is just as high amongst the professionals - and they don't wear any of the protection that the Yanks cover themselves with. Are we tougher? Nah, probably just think we are.