Easy Money (1983)

Degenerate Monty Capuletti (Rodney Dangerfield) is perfectly content spending his life drinking, smoking and gambling with his other layabout buddies. His wealthy mother-in-law, Mrs. Monahan (Geraldine Fitzgerald), has long disapproved of Monty's irresponsible behavior, but when she dies she leaves him $10 million in her will. However, predictably, there is a catch: Monty has to change his life and live vice-free for one year in order to collect the money.