One of the biggest surprises of the fall TV season may be that Fox has assembled one of the funniest two-hour weeknight packages on the air. Alongside last season’s hit, “New Girl” (“Raising Hope” returns next week), new shows “Ben and Kate” and “The Mindy Project” present a sometimes quirky, sometimes sweet and mostly promising comedy block exploring the late-20s, early-30s lives of those still trying to figure things out.

“Ben and Kate” has the more interesting setup: Free-spirit Ben Fox (Nat Faxon) moves in with his kid sister, Kate (Dakota Johnson), to help care for her 5-year-old, Maddie (Maggie Elizabeth Jones). That’s it. The simplicity is welcome considering how many series these days are built on specific premises that quickly back writers into a corner (see: “The New Normal”). “Ben and Kate” can go anywhere, and having siblings as the leads — with plenty of neuroses to probe, a la the Gellers — is a nice change. Ben may use the excuse of helping out with Maddie as his reason for relocating (that and that he lives in Sacramento — “That city can’t hold me”), and Kate may appear to have most of her life in order, but both are still relatively lost. Growing up in a troubled home bonded the two; Kate’s voiceover at the start states they raised themselves — “He never grew up; I grew up too fast.”

For years, Ben has popped in and out of Kate’s life, stopping by for a weekend of havoc here and there, often dragging Kate into whatever scheme he’s concocted. He returns this time with hopes of crashing the wedding of his ex — the one he refers to as “Mrs. Ben Fox — to win her back with the help of grappling gear and a getaway car. Kate, who manages a bar, fusses about Ben’s antics but usually finds herself willing to go along with them, such as organizing the best way to infiltrate the ex’s wedding. Kate is the responsible one, smart and pretty but slightly dorky — she likes to wear a fanny pack — and her pregnancy with Maddie while still in college was the only thing in life she didn’t plan. Johnson, whose voice gives her away as Melanie Griffith’s daughter, presents a character with more personality than the average bland TV blonde. She matches Faxon’s banter perfectly, the pair believably bickering like siblings. Faxon is endearing as the troublesome Ben, as harmless as a giant puppy one can’t help but want to play with and love.

The series isn’t without its tropes: There is the black friend, Tommy (Echo Kellum), who worships both Ben and Kate; the slutty friend, BJ (Lucy Punch), a waitress at Kate’s bar who gives Maddie makeover lessons; and then there is Maddie herself, another precocious, well-behaved child character who is wise beyond her years. “You only made one mistake in your entire life and it was the best thing that ever happened to you,” Ben says to Kate of the adorable girl, and perhaps viewers are lucky as well. An honest depiction of a 5-year-old would scare many away many a viewer. Instead, we have the grownups making messes, but at the end of the day Ben and Kate exhibit much sweetness and love for one another, along with a fierce loyalty. “We’re like two peas in like the worse pod ever,” Ben says to Kate as they hide underneath a table at his ex’s wedding reception, a habit the two formed as children when they hid from their parents’ arguing. In many ways, they are still those kids trying to steal away from the world. They have to face it, but fortunately, they can still face it together.

Creator and star Mindy Kaling has a tougher road ahead of her on “The Mindy Project” in terms of winning viewers. Her Mindy Lahiri straddles the line between likeable and not, an entitled OB/GYN determined to lead a life that will rival the countless romantic comedies she grew up adoring. She’s smart and accomplished but also short-sighted and immature. She may take on an uninsured illegal immigrant as a patient in the practice she shares with a few other doctors, but her actions stem more from an inability to say no rather than a generous heart. Afterward, she encourages her assistants to focus on finding richer clients. There’s a touch of Kaling’s Kelly Kapoor from “The Office” in Mindy, but as a supporting character, Kelly’s cluelessness worked. Mindy knows better; she just has to be reminded she does. As a lead, Mindy needs more substance.

Kaling is smart, however, and her show has a cleverness to it that hints at greater things to come. She isn’t a typical sitcom star and she isn’t afraid to make her character slightly unappealing. For example, Zooey Deschanel may turn off some viewers as Jess on “New Girl” because of the actresses’ own quirks and style, but her character remains a sweet and good person. “The Mindy Project” is more reminiscent of Lena Dunham’s “Girls,” in which the characters are delightfully flawed. It’s OK for female characters to make mistakes and act obnoxiously; it’s OK for you not to like them all that much at times. The road to self-discovery is rarely pretty. At least in the pilot, Kaling presented a nice blend: You want to shake Mindy to stop her from continuing to hook up with the sleazy, model-esque doctor Jeremy Reed (Ed Weeks), but you can’t help but feel for her on a blind date when she mentions on the phone to a friend, “Do you know how difficult it is for a chubby 31-year-old woman to go on a legitimate date with a guy who majored in economics at Duke?” Kaling is far funnier and more relatable than other sitcom leads, such as Whitney Cummings. Her talent helps you appreciate her character’s ridiculousness.

Of course, Mindy can’t see the looks she’s getting from another of the practice’s doctors, Danny Castellano (Chris Messina), a grumpy divorcee who once (rightfully) beat up a guy for having the nerve to sport a John Cougar Mellencamp T-shirt to a Bruce Springsteen show. Danny likes to swoop in and steal Mindy’s patients as well as give her unsolicited advice on how to dress on a date or act professionally. Her not recognizing the tension she shares with him means she hasn’t paid close enough attention to the countless rom coms she has devoured. They already know how to hurt each other: In one conversation, when Mindy doesn’t like Danny’s advice, she quickly refers to his divorce to shut him down. His response is meaner: She’d look better if she lost 15 pounds. Messina is charismatic and expressive as the wounded Danny, who already is far more interesting than the other characters. (Weeks is simply weak.) Anna Camp also stars as Gwen Grandy, Mindy’s best friend from college who seems willing to let Mindy’s drama distract from her stay-at-home mom life, and Stephen Tobolowsky (Toby from “The West Wing”) serves as Marc Shulman, the head of the practice.

Mindy spends the beginning of the premiere in jail, recounting her steady diet of Meg Ryan flicks and the relationship she had with another doctor (played by Bill Hader), who soon dumped her for the office’s Serbian bagel girl. “Are we 100 percent sure she’s not a war criminal?,” Mindy drunkenly asked the crowd at the pair’s wedding before bolting with a bottle of bubbling and soon riding her bicycle into a stranger’s pool, hence her arrest. The way she met her ex (they got stuck in an elevator together) had her convinced she was living a life worthy of a movie (“I’m basically Sandra Bullock!”), but now she’s back at square one when it comes to love. Turning off When Harry Met Sally, which she watches in the doctor’s lounge after a delivery, would be a good start. “Maybe I won’t get married, you know?,” she tells Danny. “Maybe I’ll just do one of those ‘Eat, Pray, Love’ things. Ugh, no, I don’t want to pray. Forget it. I’ll just die alone.” That may be easier than waiting around for things to develop with Danny. But “The Mindy Project” is worth the wait.

Sarah Carlson is a TV Critic for Pajiba. She lives in San Antonio.