@psychmomma , we did have a safe phrase when my MIL lived near us and started to rant. Someone would slosh their drink and say, “Cleanup on aisle 6!”
@threebeans , I would probably say don’t be afraid to take some time to yourself. Step out of the room, etc. Be polite. Don’t quiz people over life choices. 
My H is from India and he did not grow up with American holidays so he, along with not being sentimental about ANY (here or there), has never been big on traditions. I used to do a Christmas decorating, presents but as kid grew into his teens no one cared. Plus our lack of religion- his or my childhood ones. We developed our two culture (veg/non) T’day dinner and have favorite must haves. However, when my mother in law is with us (with her US D usually) she just doesn’t get the parade/food…
Great thing about the US is the mixing of cultures with every generation- even if it is within the same religion. Every family has its ways and changes. Glad we’re all not stuck with what past family did- we can take what we like and discard others even if others do them.
I picked my MIL and her husband up from the airport yesterday. Aside from listening to a 40 minute monologue about her neighbors health (who I do not know), yesterday went ok. The first day usually does. She starts getting snarky the next day or two, so I’m trying to remain calm.
She’s one of the most jealous women I know. It’s hard to be around that. You’d think after 40 years she’d get over that. I sure do miss my ex-SIL at holidays to lean on and commiserate with! DH’s are totally blind to her quips, jealousy and needling. She’s so very discrete with them.
Holidays at my in-laws are always tense and there is almost always some blow up but last year Christmas took the cake. My MIL is very opinionated, very liberal, and very inflexible and of course never wrong. My son is the same so it is always interesting.
We were at her house for 2 days and on the evening of the first day she started talking about why would kids choose to go to a certain school (large flagship highly rated B school) as it was a bad school, ugly campus, and offered nothing. My son mentioned that a lot of his friends chose the school and that he actually thought it was a beautiful campus. A discussion ensued with my MIL demonstrating her 40 year old knowledge of the school and my son son pushing back it is a good school and nice campus. It ended with her telling him that if he thought the school was so great he didn’t deserve to go to the school he was attending (her alma mater). My son kept his cool and the night went on.
The next day, just before dinner, a political discussion broke out, I don’t even remember the topic. In the end my MIL shouted that it was her house and that she would never allow anyone with a differing opinion politically to be in her house. This set off my son (and me) and then it was on. I tried to play peace maker while my wife and son started packing up to leave. I pointed out my son had different political opinions and had felt pretty attacked, while keeping quiet the whole trip and then when he finally stated an opinion she threw him out and essentially told her grandson to never come back. She countered that she never attacked him and when I pointed out the “you don’t deserve to go to MY school” comment she denied she ever said it. My BIL and nephew (who can do no wrong) thankfully jumped in and agreed with me and she sheepishly had to say “well that’s not what I meant”. Cooler heads prevailed and we had dinner and then left for home. The two have not seen or spoken since.
Tomorrow should be interesting. I know my son will take the approach of just sucking it up for a day but I don’t trust my MIL to not go down that path again. The thing I really dread is my youngest would be a great fit at the school that started all of the problems so we may have to go down the same road a couple of years from now.