CONTRACTS: Abby said to Ben, "I will pay you $800 to wash and vacuum my car tomorrow at 3pm." Ben says, "I'll be there." At 3pm, Ben doesn't show up. Both Abby and Ben are over 18 years old and of sound mind. There are no laws prohibiting this activity or contract. Do not assume any other facts not mentioned here.

(1) List the elements of a CONTRACT, (2) go through each element by applying the facts, (3) answer whether there is a valid contract and if it is enforceable against Ben.