An engaging idea gets mostly lost amid underdeveloped characters, a pointless subplot and creepy CGI in Fred Claus, a children's film about adult regrets and recriminations. Aside from some terrifically touching fraternal moments. courtesy of Paul Giamatti's utter submergence in his role as a self-effacing Santa Claus, this comedy about St. Nick's black-sheep brother is like getting that Christmas toy that looked so exciting in the commercials but then really wasn't fun after you unwrapped it and started playing with it.

In a prologue set in a storybook Germanic woods, six-year-old Fred meets brand-new sibling Nicholas, and through the years finds his love for his baby brother turning to resentment because of his mother's (Kathy Bates) one-sided attention and praise for her "perfect" younger child. Nicholas is anointed to actual sainthood when he grows up—freezing time, in the film's logic, for the saint and his family and spouses.

Cut to present-day Chicago, where Fred (Vince Vaughn) is a constantly broke and hustling repo man, whose soft and decent side we're clobbered with in his only-in-the-movies surrogate-dad relationship with a little black kid (Bobb'e J. Thompson) who comes in through the fire-escape window to visit with him. The fast-talking Fred—co-producer Vaughn riffing deadpan improv, which comes off like Christopher Walken trying to do Robin Williams—gets arrested for a scam that's neither clever nor roguishly charming, and has to phone little bro for bail and to "borrow" 50 G for a business venture. Santa says fine, if Fred will come to the North Pole to visit and spend a few days nominally "working" for the money.

On the outs with his meter-maid girlfriend Wanda (Rachel Weisz, inexplicably playing a transplanted Londoner whose biggest dream is visiting Paris despite having grown up a quick, cheap hop-and-skip away), Fred hits the North Pole. There, predictable family dynamics unfold, with usually formidable Oscar-winner Bates unfunny and one-dimensional as the favorites-playing mom—a potentially stock part that non-Oscar-winner Doris Roberts made into fully human flesh-and-blood on the sitcom "Everybody Loves Raymond." Complicating matters is an efficiency expert (Kevin Spacey, better than he's been in years) who wants to have Santa fired and to outsource operations.

Fred Claus wants us to love its titular big lug, but all we see, except for that painfully artificial bit with the little black kid, is a hustling user. It's one of those movies where the filmmakers give that sort of a character a devoted girlfriend but don't bother to provide a single freaking clue as to why anyone with half a brain would stay with someone like that. A second, even more ridiculous romantic subplot has head elf Willie (the digitally composited head of John Michael Higgins and body of Jorge Rodero) claiming he's in love with Santa's vaguely defined secretary/receptionist/CFO Charlene (Elizabeth Banks)—who can't even remember his name. And at Santa's beautifully constructed but unimaginatively designed North Pole village, where a small parade of overnight visitors and at least one worker are regular-sized, the movie throws out internal logic for one cheap and not particularly laff-riot visual about Santa's brother sleeping in an elf-sized bed.

The aforementioned CGI compositing of Higgins and of rapper Ludacris (in barely one scene as a DJ elf) looks off and ungraceful. Were there no little people whatsoever, in all of SAG, who could have played those unremarkable parts? The CGI flying-sleigh effects, however, are pretty remarkable and well-realized. If you really want to gift your kids with a Santa movie this year, get a DVD of The Santa Clause (1994).