Who says cartoons are just for children?

Last September, Cartoon Network launched a new programming block called Adult Swim, airing late on Sunday and Thursday nights and aimed squarely at older viewers.

The channel's experiment in adult animation has proven a success, and now it's expanding.

Cartoon Network is already airing a second season of "Home Movies" and has rescued "Baby Blues" (based on the popular comic strip) from cancellation over at The WB.

Meanwhile, new episodes of "Aqua Teen Hunger Force," "Sealab 2021," "The Brak Show," "Harvey Birdman, Attorney at Law" and "Space Ghost Coast to Coast" trickle out as quickly as the animators at Williams Street Productions can manage.

But Saturday marks Cartoon Network's big leap forward, as the channel adds a new night of two-fisted Adult Swim programming.

Adult Swim Action will air from 10 p.m. until 1 a.m. (all times Central). So far, it's an all-anime block, featuring "Yuyu Hakusho" (Japan's second-most popular cartoon after "Dragonball Z"), "Cowboy Bebop" (moving from its Sunday timeslot), "Pilot Candidate" and "Mobile Suit Gundam 0083: Stardust Memory."

The block also includes two Toonami shows with grown-up appeal, "Tenchi Muyo!" and "Outlaw Star."

Cartoon Network has aired "Gundam" cartoons before. Both "Gundam Wing" and "Mobile Suit Gundam" aired weekday afternoons as part of the teen-oriented Toonami block.

But the grim and more realistic "Gundam 0083" wouldn't fare well edited for that timeslot.

Like the other "Gundam" series, "Gundam 0083" is a sprawling, futuristic epic, chronicling a civil war between Earth and its outer-space colonies. The deadliest weapons in the war are the Gundams — giant robots operated by human pilots.

"Gundam 0083" takes place four years after the events of "Mobile Suit Gundam," as the defeated forces of the Principality of Zeon attempt to steal a nuclear-armed Gundam for use in their renewed war for independence.

As usual, the only thing standing in the way of Zeon's ace pilot is an untested Earth Federation cadet.

With the highest-quality animation and arguably the strongest story, "Gundam 0083" is the best the "Gundam" saga has to offer.

"Yuyu Hakusho" is popular in Japan but is less well known here. This supernatural series features a 14-year-old boy, Yusuke Urameshi, who returns from the dead to become a "spirit detective," tracking down demons who threaten the living.

Even though it's a children's show in Japan, it's easy to see why Cartoon Network is airing "Yuyu Hakusho" as part of Adult Swim. If you think the stink over alleged occultism in "Harry Potter" was something, just imagine if anyone thought Cartoon Network was "indoctrinating" children with Japanese spiritualism.

"Pilot Candidate" is your typical children-pilot-giant-robots-and-save-the-planet show, only it blends traditional two-dimensional animation with computer-generated 3-D animation.

Of course, the best of the lot is still "Cowboy Bebop," a stylish tale of bounty hunters cruising the spaceways in search of easy money and a decent meal.

Meanwhile, the other Adult Swim blocks are undergoing some changes, too.

First, say goodbye to the Thursday repeats. It's the price we pay for getting the Saturday block.

Second, in March the comedy-oriented Sunday block becomes a proving ground for new series pilots. First up is comic book writer/artist Evan Dorkin's "Welcome to Eltingville," airing March 3 at 10.