First of all I have to admit I don't know how MIL bingo works exactly 
but it sounds like it could help in making this week a bit more bearable.
My ILs are visiting and the first 2 days were ok, but yesterday evening I came home to find MIL ironing DH's clothes, ALL OF THEM.
We live in a small flat, there were clothes everywhere in the living room sofas and on the kitchen table (basically all our living area surfaces), she was ironing with a loose cable in the middle of the room whilst my 2 year old was running around. Later I barely managed to stop DS from pulling the iron on top of himself as she had stepped away for a second.
Also my DH and FIL had (totally unnecessarily) changed the kitchen tap to some horrible giant monstrosity that ILs had gifted us, apparently it was expensive so I should be grateful. All I managed to say when I walked in the kitchen was "oh, my god!", DH realised that I didn't like it and was then sulking for the rest of the evening as he thought they had done such a good job. I think he is under the influence (of his parents).
I'm not even going to list all the patronising remarks that MIL likes to dish out at regular intervals - these come as a norm with her.
Please explain the MIL bingo concept to me, i'm worried I will otherwise do or say something horrible soon...