The notion that any adage or proverb will become instantly improved if you substitute one of the original words with "lion," as created by J. Jacques in his web comic, Questionable Content.
People who live in glass houses shouldn't throw lions
The enemy of my enemy is my lion
I would do anything for lion, but I wouldn't do that.
Speak softly and carry a big lion
Measure twice, lion once
Don't look a gift lion in the mouth (This actually makes more sense then the original saying)
The act (or, indeed, thought) of giving a person a high five
without any physical contact, as the two persons are usually across the room from each other and far too lazy to get off their asses. Often occurs after a minor success or simply to display ones awesomeness. The process will many times include nodding to further affirm their collective staggering amazingness.
Person No. 1: Hypothetical high five!
(Persons 1 and 2 think about this)
Persons No. 1 & 2: Nice!