YOU DON'T KNOW JACK. 9 p.m. Saturday, HBO.

ACTORS WHO appear in HBO films are fond of noting the network's willingness to tackle subjects that movie studios wouldn't touch because they're controversial or don't do much with special effects or focus largely on people well over 35.

It probably doesn't hurt, either, that a movie actor who does HBO is practically guaranteed an Emmy nomination, the combination of big names and extended character treatments being like catnip to the academy.

HBO can probably count on a slew of nominations for "You Don't Know Jack," its biopic of euthanasia enthusiast Dr. Jack Kevorkian, which premieres Saturday with Al Pacino in the title role. Backing up Pacino: Susan Sarandon, Brenda Vaccaro, John Goodman and Danny Huston, each of whom is as good as anyone could hope.

So if I can't work up much enthusiasm for "You Don't Know Jack," it's not the cast, I promise you. It's probably just that after spending more than two increasingly dispiriting hours with Pacino's raspy eccentric, I still didn't know a lot more about Kevorkian than I had going in. Or at least a lot more that mattered to me.

With a script from Northeast Philadelphia native Adam Mazer that's directed by Barry Levinson, "Jack" whisks us through several turbulent years in the life of the man who eventually served time for murder after assisting in the deaths of 130 people.

The film doesn't attempt to depict all of them, of course, but what it shows is sad and occasionally downright bizarre, given Kevorkian's penchant for tinkering with machinery.

Though it doesn't place the legal system or the prosecutor (Cotter Smith) who targets "Dr. Death" in the most flattering light, "Jack" doesn't demonize it, either, and seems at pains not to take a stand for or against Kevorkian's beliefs. Which leaves us with a character study of a guy who's undeniably a character.

"I think the title is apt because you don't know this guy. And, hopefully, in the movie you still don't," Pacino told reporters in January.

That might be enough for him, but it wasn't quite enough for me.

Starz's funny Fridays

I wouldn't usually waste ink on behind-the-scenes changes in TV, but a shakeup this week at Starz in the department that develops its shows came just days before the premiere of the premium-cable network's new dramedy "Gravity" (10:30 p.m. tomorrow) and the return of "Party Down" (10 p.m. tomorrow).

You don't have to be a member of the suicide survivors support group that's the focus of "Gravity" to find the timing troubling: New executives often feel little affection for Other People's Projects.

Thanks to the estimated 1.3 million who tuned in for the first-season finale of "Spartacus: Blood and Sand," fans of CGI and gladiators have little to worry about. That one will be back.

Here's hoping Chris Albrecht, the former HBO chief who took over the reins of Starz a few months ago and has been scooping up programming that might have "Spartacus"-like appeal - a 10-part "Camelot" for next year, an eight-parter for this summer based on Ken Follett's "Pillars of the Earth" - can also embrace the small and quirky.

"Party Down," from "Veronica Mars" creator Rob Thomas, is something of a critics' darling already, and while I never got around to reserving a seat on the bandwagon, it grew on me considerably in its first season.

The show follows the adventures of a group of Los Angeles-area cater-waiters and stars Adam Scott, Ken Marino, Lizzy Caplan, Martin Starr and Ryan Hansen as people whose big breaks haven't yet arrived (and may not be coming).

The hilarious Jane Lynch, a regular last year, has this new gig on Fox's "Glee" - maybe

you've heard of it? - but is expected back for the season finale. Her shoes can't be filled. Fortunately, "Will & Grace's" Megan Mullally, joining the team as a middle-aged woman whose Hollywood aspirations are for her teenage daughter, has shoes of her own.

"Gravity," another ensemble piece, is considerably darker than "Party Down," but in some ways I found it funnier, with a vibe that rather reminded me of Showtime's "Dead Like Me."

"Breaking Bad's" Krysten Ritter plays Lily, who summons up a dream lover after swallowing some pills and becomes obsessed with reuniting with him, while Ivan Sergei is Robert, an eye doctor who tried to kill himself after his wife died.

Forced to attend meetings of a group of suicide survivors - led by Ving Rhames as an ex-baseball player now in a wheelchair and including Rachel Hunter as a former supermodel - the pair quickly connect under the perhaps too-watchful eye of a police detective played by "Gravity" co-creator Eric Schaeffer (whose FX comedy about eating disorders, "Starved," makes this concept seem mainstream).

I'm not sure where Schaeffer's taking his character - or "Gravity" - but for now I'm hoping it's not off a cliff. *

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