Jim Carrey may be unconvincing as a TV newsman in "Bruce Almighty" -- he wears khakis and plaid shirts on the air, he needs a haircut, and he hold his microphone as if he doesn't know which end is up -- but as an everyday joe temporarily granted all the powers of God, his return to crackpot comedy is a most welcome summer movie treat.

After some angry finger-waving toward heaven over a fairly minor bout of bad luck (he's been passed over for an anchor job, he crashes his car into a lamp post and he can't seem to housebreak his dog), Bruce Nolan (Carrey) becomes God for a spell when the Big Guy (Morgan Freeman having a little fun with his noble image) gets fed up listening to him whine. God decides to show Bruce how tough the job of the Almighty really is, and humorous havoc ensues.

Of course, at first Bruce just has a ball being omnipotent. He grins impishly to himself as his live-in girlfriend Grace (Jennifer Aniston) says over breakfast, "I woke up this morning and I swear my boobs were bigger." When he comes across some muggers who beat him up the day before and demands an apology (in the most Biblical language he can muster), the leader of the gang says "You'll get your 'sorry' the day a monkey comes out of my butt."

"What a coincidence," replies Bruce...

He also uses his powers to get ahead at work (giving a backstabbing anchor a squeak-toy voice) and to romance Grace (he erases the clouds and pulls the Moon closer to the Earth to enhance a night of amour).

But then come the thousands of voices in his head -- prayers he magically organizes as emails and automates his system to reply "yes!" to all. And soon he learns there are consequences to his actions (tidal waves flood Japan because of "unusual lunar activity," 11,000 lottery winners get only $17 each from the jackpot).

The overall story arc of "Bruce Almighty" is predictable -- Bruce has a lesson to learn, after all. But the writing (by Steve Koren, Mark O'Keefe and Steve Oederkerk) is wickedly witty ("It was nice to meet you," says Bruce when freaked out by coming face-to-face with God. "Thank you for the Grand Canyon. Good luck with the Apocalypse. I gotta go.") and the film hits home runs with both highbrow and lowbrow gags.

Just as importantly, Carrey's performance strikes a similar, well-conceived balance. He's not an all-zany-all-the-time, "Ace Ventura" kind of guy. He's a believably regular guy prone to sidesplitting fits of Carrey-esque berserkness.

In fact, "Bruce Almighty" is one of Carrey's funniest and smartest movies -- right up to the point when the screenwriters and director Tom Shadyac ("Ace Ventura," "Liar Liar," "Patch Adams") reel in the clever comedy and roll out the stock plot conflicts (Grace walks in on Bruce being kissed by a sexpot anchorwoman and now he must win her back!) and the cloying, heavy-handed moral-of-the-story messages.

People don't realize "they have the power," says God, "to be their own miracles."

Oh, brother. What happened to the laughs?

Carrey can't carry this cheaply sentimental stuff (and he shouldn't have to), so as a result the movie almost crashes and burns in its last reel. (Closing-credit outtakes to the rescue!) But even blinded by mawkishness, Shaydac manages to land this plane on one engine with the help of his great cast.

Before he's called on to get gushy, Carrey finds a hilarious but entirely human happy medium between his wacko side and his Everyman appeal. Flexing the talent she proved she has in last year's indie hit "The Good Girl," Aniston is quietly brilliant without doing any scene stealing. Her character has so much depth and resolve that you root for Grace when she leaves Bruce after the co-anchor kiss, because she brought such an emotionally true, genuine-couple dynamic to their relationship. And Freeman is wry yet fervent and humble yet commanding in his performance as the stern but serene and self-amused God.

These three make it easy to forgive "Bruce Almighty" its shortcomings (especially since Aniston helps the film to find its true heart at the very last minute) -- even if it's hard to forgive the writers for running out of droll, dry ink and filling their quills with sap as they wrote the picture's last chapter.