I will cashApp whomever money for lunch tomorrow ($15) to whomever could give the best definition, and example of using callbacks that fit in a tweet.

Winner decided by:

1 like = 0.5 point
1 RT = 1 point

Participation is consent for you to be included in my TDD talk at @MagnoliaJSconf

No, you can not give multiple tweets to increase your chances.

Excluded as well is @jchiatt from participating