It Could Happen To You.But it probably won't. This engagingly preposterous fairy tale, all about the joys of altruism, tops off its cast of caricatures with a cop (Cage) who pledges downtrodden waitress (Fonda) half his lottery take in lieu of a tip. The gist of their roles is to act inhumanly simple and virtuous, in contrast to his grasping, baubled wife (Rosie Perez). Cage proves he could do a lifelike Robin Hood, while Fonda would be more than winsome in The Princess and the Pea. Here it is a pleasure to be persuaded to suspend disbelief. After 101 minutes, though, it's back to the real world, where giving has lost its good name. B

