Look a Cow
Whenever we get in the car, the game is on. No one has to say anything. The first person to see a cow and say Danny Devito's line from Throw Momma From the Train, WINS!

Josh beat me at this on the island of Oahu driving out by Laie. He rubs it in with glee.

Say, "Ahh."
Whenever someone chokes or gags (usually the baby) they have to let everyone know that they're OK by demonstrating that their windpipe is clear. Josh started this with our oldest and it never went away.

Love you miss you
When our oldest was a baby, she would say goodbye like this: "Bye, Mommy! Love you miss you." It stuck. Our extended family and some friends know and use "LYMY" as a closing in their emails and letters.