I guess my DIL would categorize me as the MIL from you know where since she has only bothered to show up at our house for a total of 4 whole minutes since my son married her. I know that sounds silly except her parents live 4 miles from us and she's spent approx. 3 weeks there. We've invited her out to dinner, breakfast, lunch, etc. She never bothers to show up. I give up.
My SIL is another story. Sometimes I'd like to say "why don't you call your mom and talk to her". It's pretty funny when you think about it.