With some spunky cameo roles from Jay Leno and Meryl Streep, the Farrellys, adopting a story written in part by Charles B. Wessler and Bennett Yellin, take us inside the lives of Siamese twins who the Farrellys of all people remind us ironically should be called by the politically correct term, "conjoined twins." In one scene, Matt Damon in the role of Bob Tenor reminds a guy who calls them by the less correct term, "We're not Siamese...we're Americans." We wonder just how many times he has had to feed that line to people so likely to use pejorative colloquialisms.

Now thirty-two years of age, the conjoined twins, Bob Tenor (Matt Damon) and Walt Tenor (Greg Kinnear), seem at first to have merely their sleeves sewn together. Ultimately they're going to strip down to the waist to show us in the audience that while they have four legs between them, they are bound at the stomach which looks convincing thanks to the miracle of movie prosthetics. The film does appear to be going in the direction of a one-joke comedy and, in fact, we get what we expected. But things turn weepy when the brothers make the decision of their lives after which much of the joys and woes that the two have shared for three decades are threatened.

The slapstick element appears largely when the Tenors are playing baseball, football, ice hockey and prize-fighting, showing us in the audience that those handicapped by their forced proximity can actually stop the hockey pucks better, fight more creatively, confuse batters and base-stealers, and play defense and offense at the same time in the rough-and-tumble of the gridiron. The romantic element takes center stage as the two meet the women of their dreams; Bob, clearly the shyer sib, beings a relationship with May (Wen Yann Shih) whom he spoke with for three years on the Internet but did not tell about his physical complexity, while the more assertive Walt become entwined (so to speak) with the well-appointed April (Eva Mendes).

This is Greg Kinnear's movie given his character's love of acting. Walt puts on a one-man parody of Truman Capote before an appreciative audience in his small home town (where he flips burgers at a fast (really really fast) food restaurant they own and mentors the reluctant Bob repeatedly to get with the romantic program. Seymour Cassel gets laughs as the Tenors' Hollywood agent, zipping about in his wheelchair in a film that has a ball sending up the handicapped (Fellini had some laughs at the expense of the blind, so why not?).

Kinnear and Damon have a ball together in roles that require chemistry beyond the call of duty while Cher does a hilarious parody of her usual diva-like attitude, in one case telling her bedded boyfriend to "go to sleep: you have a geography test tomorrow." Some gags work, others fall flat. But isn't that the way of all such movies?