Throw-away words

So I was at Kelly's sister's house for dinner tonight. Her sister is SO cool. The food was amazing, and it was funny to watch 3 boys ages 6 - 10ish act all rowdy and boyish at the table. When I was a kid and living at home, my two brothers were completely outnumbered by girls and couldn't get away with anything. We would even check their lunch bags to be sure they hadn't taken too many snacks. Poor guys, but still. You just don't go hogging the Nutty Bars.

Managed to put my foot in my mouth when I used the word "stupid" as part of a story I was telling. The kids became very still and just stared, which is when I remembered that they don't use the word "stupid" at their house. (I should say here, though, that their mom says calling someone a jackass is just fine because it's a zoological term.) I tried to cover with "I mean, um, I felt so silly. Yes, silly." But that damage was done. I'm now That Potty-Mouthed Friend of Kelly's, and the kids probably prayed for me tonight when they went to bed. Sigh. Does anyone else know of families that have a list like this, where words other than the obvious things like swearing and generally offensive terms are banned? How do you decide which words to pick? Like, if "stupid" is out, can you use "dumb"? And if you can't say "shut up," can you say "shut your cake hole"?

ps. I read "The Enchanted April" by Elizabeth Von Arnim during the DEAD conference today and it was perfect. Highly recommend it as a beach read or an it's-raining-and-I-would-rather-be-relaxing-in-Italy read.