iZombie' a happy surprise, 'One Big Happy' less so

* iZOMBIE. 9 tonight, CW57.

* ONE BIG HAPPY. 9:30 tonight, NBC10.

NOTHING says St. Patrick's Day like a nice bowl of microwaved brains with hot sauce.

No, really.

Why else would the CW introduce "iZombie" tonight?

If your plans to honor the saint involve something livelier than new and returning shows on TV (and the Yahoo premiere of the sixth season of "Community"), you might want to check in first with Liv Moore (Rose McIver), an up-and-coming medical resident who went to a wild party one night and woke up in a body bag.

Now she's TV's palest heroine, works in the morgue (because otherwise she'd go hungry) and - because this is a TV show - uses one of her newfound skills to solve crimes.

A smart, sometimes bittersweet comic-book adaptation from Rob Thomas and Diane Ruggiero-Wright, two of the best brains (sorry) behind "Veronica Mars," "iZombie," like "Jane the Virgin," plays much better than it might first have sounded.

Liv, whom we meet six months after her very bad night, is an undead shadow of her former self. Having abandoned her medical career, her seemingly perfect fiance, Major (Robert Buckley, "One Tree Hill"), and any ambitions she once had, she's about to find reasons to carry on through interactions with her geeky boss, Dr. Ravi Chakrabarti (Rahul Kohli), and a struggling homicide detective, Clive Babineaux (Malcolm Goodwin).

McIver shines in the moments in which Liv, whose new diet confers certain privileges, briefly experiences the world from another's point of view, but it's her ability to make Liv's plight seem almost plausible that carries the show.

NBC, once the network of "Will & Grace," has been trying to find the funny in nontraditional families for the past few seasons.

It's not going so well.

There was "The New Normal," Ryan Murphy's PSA-disguised-as-a-sitcom about an affluent gay couple in L.A. who invited their surrogate and her 8-year-old daughter to live with them.

Then came "Sean Saves the World," in which Sean Hayes ("Will & Grace") played to the last row of some vast, imaginary theater as a gay divorced man with a 14-year-old daughter, a wisecracking mother and a mercurial boss, all but the daughter so over-the-top it was exhausting to watch.

Tonight, after the return of "Undateable," we get "One Big Happy," starring Elisha Cuthbert ("24," "Happy Endings") as Lizzy, a lesbian whose plans to conceive and raise a baby with her straight best friend, Luke (Nick Zano, "Happy Endings"), hit a bump when Luke falls for an ironically named Englishwoman named Prudence (Kelly Brook, "Smallville") and quickly decides to marry her.

Ellen DeGeneres is an executive producer. The show's creator, Liz Feldman ("2 Broke Girls," "Ellen"), drew from her relationship with her own best friend, with whom she once planned to have a baby before he met someone. (They didn't go through with the plan.)

It's not an unpromising premise and Cuthbert's character, a control freak who's had trouble with romance, isn't stereotypical. But Luke's written as less than bright and Prudence as downright cartoonish, to the point where, four episodes in (the most I could take), it was impossible to imagine these three co-parenting a puppy, much less a child.