this is old news, so it's possible that i am the last person in fandom to know about it, but...

the broccoli test
as explained by gwyn_r:

sherrold was the one who came up with the broccoli test idea when she was living in L.A. with a friend, C. As legend, and my mind filling in blanks, would tell it, Sandy and C were at the grocery store, on opposite ends of the produce section, and Sandy was trying to tell C to pick up some broccoli without shouting across the store at her. No amount of pantomiming and mouthing of the words could get the point across to C, and Sandy apparently told her (we were all in the midst of Professionals-mania then), "Doyle would have known Bodie wanted him to pick up some broccoli with just a raise of his eyebrow!" or something like that. Hence, Bodie and Doyle would have passed the broccoli test.

i spent more time than i will ever admit poring over the both the original multifandom and also the sam/dean explorations of the theme, but i love that it can also be used in real life.

lesbian telepathy is henceforth to be known as broccoli. just fyi.

( some of my favourite examples: supernatural, house, sherlock homes, harry potter )