Chomping at the bit. The correct phrase is “champing at the bit” – which, in a classic case of proper English trumping logical English, doesn’t make as much intuitive sense.
Basically, the word chomp was derived from the word champ, which means “to bite or chew loudly.” But chomp is a transitive verb, meaning it needs an object — so while “chomping the bit” is grammatically correct, “chomping at the bit” isn’t.
Around this point in the list I would expect you’re thinking to yourself: “Wait – homeboy is giving us a lesson on transitive and intransitive verbs? The very same guy who does lists on beer pong rules and the sexiest items for sale at the 99 Cents Only Store? What the hell?” And you make a valid point. But hey – at least it’s not the Internet’s 12 billionth article called “Why the iPad sucks but we’re gonna buy it anyway.”