Lotus (my) Family: my mother is a football freak. Cute guys, tight pants, side bets -- what's not to like? Dad -- not so much. Mom tried an American TG meal (veg) exactly once, at one of my brother's behest. Total flop, though she is normally a very good cook. Anyway, it interfered with football. Back to the standard: dim sum ordered in, which only requires steaming or refresh steaming, enough for everybody present, twice (at least). Dad takes charge of the kitchen, den and non-footballers with games -- we had serious chess tourneys when I was growing up -- conversation, maybe crafts (one SIL knits, kids color, read, or whatever, unless they are budding footballers), and music. The footballers do their football thing in the living room, keeping the non-footballers posted when they come in for food refills. People wander around. This has survived transitions to my brothers' houses, and my SILs actually like this very easy program. For New Year's, which we spend with my family, we go to the Temple in the morning, pick up the dim sum on the way home, and everybody watches the Rose Bowl. Even Dad and I will sit through this one and ONE is fun.
Plum (DH's) Family: football freaks; they all live in HugeU City, all follow college football, and that is where we go for TG. Traditional US TG meal with veg additions/substitutions when necessary. Dinner time is set for when there is an anticipated football break, and all TVs, radios, phones, etc. go off during dinner. After dinner the choices are a walk or more football. Everything, in every room, is on again! More football! More! More! Then dessert is served, and there is usually, by this time, no more football, so there is generally a movie, which varies, conversation, and clean-up before everyone packs it in for the night.
All of our houses have places where non-footballers can do other things, thank goodness. If the houses did not have separate living rooms and family rooms, dens, big kitchens with breakfast rooms or some separation, I can see the football thing being overwhelming and absolutely miserable for half the party at all times -- the footballers are miserable if it is off, and everyone else is miserable if it is on!
I suggest some compromise, and this has to come from the hostess and host. Maybe SIL could pick ONE game, maybe others might even enjoy ONE game, and dinner is set outside that game's time? During dinner, everything off, like my husband's family does, and then if SIL wants more football, she could curl up with a small TV in a bedroom (if there is no den) or with her tablet and earphones and watch to her heart's content?
But she has to be quiet and respectful of people doing other things and needs to understand that not everyone shares her tradition and passion for all football all the time, and that others must be allowed to do other things.