All a Big Game

We were at the checkout with a small package of bagels and a gallon of drain-cleaning liquid.
The assistant turned to us with a happy grin.
"Looks like you guys are stocking up for the Big Game."
We possess next to no knowledge about sports. We were not even aware there was a Big Game, and we found out later that the event in question was a little something known as Superbowl Sunday.
Spouse and I glanced quickly at the bagels, and the cleaning fluid, and wondered what sort of stocking up he thought we might be doing.
Spouse nodded, simply, one must understand, to be polite.
We only knew this much about the Game: it was Big, and people ate bagels and cleaned their bathrooms in the midst of it. Our embarrassed silence, along with our inability to look him in the eyes, ought to have been a clue.
The fellow, unfortunately, did not take the hint offered to him, and he proceeded to delve into conversation with us about the mysterious Game.
"So, who are you rooting for this time?" And he named two teams, both of which I have since forgotten.
Spouse, not sure whether it was football or baseball or miniature golf or swimming being discussed, promptly concluded the chat by suggesting that it did not really matter who won, as long as great fun would be had while watching it.
The fellow behind the counter was, to say the least, a trifle stunned, until it dawned on him that we probably were making it up as we went along, and that he ought to let us hurry on our way with our bagels and our cleaning supplies.