Here are a few...
The Rule of Eights:
Any number can be made eight by minus-ing or adding.
The Rule of 5 + 12:
Every number under five can equal twelve in different ways.
The Rule of Steps:
Every person is between one step and a million bajillion steps away from each other at any given time.
p + p = s + 1 +/- milbajil
The Rule of Brussels Sprouts:
There are 5 brussels sprouts in the world.
The Law of Biggest Loser:
If someone on the biggest loser lost a million pounds, and another person lost one, then a million divided by a million equals zero.
I mean one.