Worlds collide at this year’s Tribeca Film Festival, which begins tomorrow — or, at least, that’s the central theme that keeps popping up as one rifles through a few dozen of this year’s 120 selections.

BABY MAMA
First Screening: Tomorrow, 7:30 p.m.

Singled out to screen tomorrow evening as the festival’s opening-night headliner, “Baby Mama” is sweeter and smarter than many will be expecting. Starring Tina Fey as the walking corporate cliché and Ms. Fey’s “Saturday Night Live” cohort, Amy Poehler, as her blue-collar polar opposite, the movie sees its central conflict clearly and cynically: After Kate (Ms. Fey), who desperately wants a child, is told by a doctor that she’s infertile, she decides to shell out $10,000 for a surrogate. But when Angie moves in, it becomes clear that the corporate exec and the paycheck-to-paycheck surrogate — one living in a world of organic foods, the other in a McDonald’s Happyland — can’t quite relate.

There’s a subversive bit of gender-bending occurring here. The women stand tall, center stage, as the substantive odd couple, while Greg Kinnear plays the token, one-dimensional romantic interest. In all likelihood, it’s thanks to the maternal focus that the humor (courtesy of writer-director Michael McCullers) is more about the characters than their bodily functions. There’s also a momentum to all this silliness that keeps “Baby Mama” feeling spry, with material and characters to spare.

After last year’s opening-night celebration at Tribeca, which was packed to the gills with short films about global warming and attended by Al Gore, “Baby Mama” is a starkly mainstream, mild-mannered change of pace. Of course, there’s something distinctly New York about watching two “SNL” stars coming into their own. The obvious rapport shared by Ms. Fey and Ms. Poehler makes for a feel-good formula, but not a lazy one; “Baby Mama” is unapologetic about wanting to be the kind of comedy that can transcend genders and age brackets.

GUEST OF CINDY SHERMAN
First Screening: Sunday, 9 p.m.

Whereas “Baby Mama” is about living with an unfamiliar guest, “Guest of Cindy Sherman” is about a beloved guest who finds himself overcome by a sense of alienation.

Tom Donahue and Paul Hasegawa-Overacker’s documentary about a sarcastic art commentator who unexpectedly fell in love with one of the artists he was criticizing opens in the mid-1990s, as Mr. Hasegawa-Overacker is assembling his public access television show “GalleryBeat.” From the outset, it’s clear: He’s an outcast peering into the art world, ruffling the feathers of the establishment as he comes to question all that others hold sacred. Yet from her very first meeting with Mr. Hasegawa-Overacker (known to most as Paul H-O), the famed photographer Cindy Sherman took a liking to him, and agreed to sit for an array of in-depth interviews.

The movie, though, is less about one art lover finding love and acceptance than about the stress and anxiety that overcome the couple as they try to build a bridge to connect their separate worlds. We watch as Mr. H-O is regularly invited to elite gatherings and allowed behind the velvet rope, even offered a seat at the head table. But in one of the film’s darkest moments — recorded by Mr. H-O, who took his camera everywhere he and Ms. Sherman went — he recounts the humiliation he felt when he realized that his name card at one gala event read simply: “Guest of Cindy Sherman.”

“Guest of Cindy Sherman” evolves from a story about the New York art scene at the close of the 20th century to an intimate profile of both an outcast and an insider, and emerges as a surprisingly powerful psychological drama about a man lost in the glare of the spotlight and immersed in a frantic bid to rediscover himself.

BOY A
First Screening: Friday, 5 p.m.

Naïveté gives way to terror in both “Boy A” and “Waiting for Hockney,” two movies about scared young men as they teeter on the brink of failure.

John Crowley’s “Boy A” recounts the struggles of a 24-year-old Brit named Jack (played eerily by Andrew Garfield) as he attempts to fit into a new town while keeping his dark past a secret. As he starts to find his footing, making friends and catching the eye of a young woman in his office, a series of flashbacks sheds light on his criminal past and how it might destroy his future.

As it tackles the thorny subject of redemption — both seeking it and granting it — “Boy A” thrives on Mr. Garfield’s painfully innocent and vulnerable performance. We think we know Jack, but as the circular plot winds back to the beginning, everyone’s assumptions are turned upside down.

WAITING FOR HOCKNEY
First Screening: Thursday, 7:30 p.m.

Much the same could be said for the thrilling documentary “Waiting for Hockney.” It concerns Billy Pappas, a 38-year-old man who has effectively spent the last decade of his life crafting and refining a single work of art. Convinced that with enough time and practice he could create a work of art so startling and captivating that it would catapult his career, “Hockney” finds Mr. Pappas with a completed sketch — an intricately detailed drawing of a celebrity’s face over which he has spent 10 years obsessing. With the support of family and all those who have backed him emotionally and financially, the documentary records Mr. Pappas’s far-flung attempts to track down his idol, David Hockney, because he believes the artist will be the one to champion his work and introduce him to the art world.

Mr. Pappas may be naïve — or worse — but there’s real drama to be found in the bold nature of his journey, which concludes as he pulls into Mr. Hockney’s driveway, his life’s work sitting in the trunk.

ssnyder@nysun.com