Here's a four-word definition of a high-concept movie: Jim Carrey is God.

Before studio executives read a word of the script for "Bruce Almighty" or heard anything more about the story, they must have been chortling at the very idea of Ace Ventura playing the King of Kings. A benign physical comedian subbing for an all-powerful, seemingly humorless Lord - what a merger of talent!

With a little setup - let's assume Bruce is a frustrated Buffalo TV reporter whose withering faith prompts God (Morgan Freeman) to give him a shot at his job - you can make up your own checklist of jokes.

Wouldn't Bruce try out his new power in trivial ways, say by sending a gust of wind up a pretty girl's skirt or willing his incontinent dog to use the toilet? Check.

Wouldn't he whip up a few exclusive news stories to endear himself to management and win that anchor job? Check.

Wouldn't he use it to enhance his girlfriend's sexual pleasure and, for his own amusement, make her breasts larger while he was at it?

Okay, you may not have thought of all of these, but director Tom Shadyac and his trio of writers did, and so did the marketing people who cribbed them for the film's hilarious highlights trailer.

Fortunately, there are many more jokes where those came from.

Shadyac and Steve Oedekerk, one of "Bruce's" writers, launched their careers with Carrey's Ace Ventura character, and they know how to tailor material to the star's buffoonish gifts. The wonder is that they didn't think of this earlier.

When Carrey is doing his thing as the Almighty, histrionically whipping up one miracle after another and relishing the power, "Bruce" has you spring-cleaning your lungs with laughter. But you are made to pay for it with a third-act sap-rising that's as thick as the final reels of "Patch Adams."

That 1998 film, starring Robin Williams as Bozo the Doctor, was also directed by Shadyac and co-written by Oedekerk, and they still haven't learned when to turn the spigot off on the sentimentality.

Bruce can't just have a ball as God and be done with it. He has to lose and win back his girlfriend, learn humility through prayer, and keep a straight face when God gives him the meaning of life in the form of a riddle - don't look for a miracle, be the miracle.

To our benefit, Carrey does treacle with an earnestness that eludes the doe-eyed Williams, and he's ably assisted in both the comedy and bathos by an adept Jennifer Aniston, who continues her transition from TV to film star, and the melodious, whimsical Freeman, who's the most cordial screen deity since George Burns played himself in "Oh, God!"

But look out for Steve Carell, the TV comedy actor ("The Daily Show With Jon Stewart") who nearly steals the entire movie in a scene where his blow-dried anchorman has an on-air meltdown ordered by an avenging Bruce. It's a scream.