Biathlon, ie skiing and shooting is a fairly nice sport to watch according to my mum. The shooting events are game changing so it become exiting. So just randomly, your task is making this sport big in the US.
Simple: Cool down the sun a bit so that there is quite an amount of snow in the whole US during winter and give the gun nuts more rights and you have a biathlon nation.
Otherwise you could just try to find some way to give the US Whistler.
But seriously, I often wondered why Biathlon isn't a big thing in the USA.
It is sports combined with shootin' guns!!! Also, large parts of the North of the USA experience their deal of snow in the winter (ice-hockey is popular in that part of the USA, too, despite the fact that others invented it and actually compete against Americans ).