Jim and Bob bought one lottery ticket each week for five years. Each paid half of the price of each ticket. Bob got tired of losing and told Jim he did not want to buy tickets anymore. Jim said "That is OK, if I win I will still give you half." The next week Jim won the jackpot of $2,000,000. When Bob said to him, "You promised to pay me half if you won" Jim said "Tough, you did not pay a cent for the winning ticket."

Does Bob have any hope of suing Jim under contract law for one-half the winnings? Why/Why not?