CD-ROM magazines offer preview of Internet ads of the future.

On the computer screen is the lobby of a virtual megaplex. To the left are the open doors to two movie theaters, on the right is the concession stand.

Animated "Butterfinger BBs" (new ball-shaped candies from Nestle SA) dance out of the concession counter, floating like chocolate-covered bubbles across the screen. Do you click on the Butterfinger display? Of course you do.

The next screen is a museum of Butterfinger lore. Push a button to learn the effects of Butterfinger BBs on the brain. An animated cross-section of a human body, kind of like the diagrams you saw in anatomy films during your ninth-grade biology class, shows a man chewing and swallowing a BB. When the candy hits his stomach, it sends animated pleasure rays up to his brain, causing it to spin around and pulsate, while his eyes bulge with joy.

"Crispity!" shrieks the animated man.

The anatomy show is nothing compared to the history display in the interactive museum, in which a primitive man is shown eating an older, more powerful version of the BB and his head is blown clean off- shouting "Crispity!" as it plummets into a canyon.

It's funnier than it sounds, especially if you happen to be about 15 years old, which of course is the target audience.

The ad is one of several animated, interactive commercials to be found in the latest issue of Launch - a "magazine" that's put out on CD-ROM instead of paper stock. It's produced by Santa Monica-based 2Way Media Inc.

There is not a huge market for interactive ads, which is one reason hardly anyone produces them. The Internet is too slow for the kind of animation seen in the Butterfinger BB spot. And although several CD-ROM magazines have been launched in the past few years, Launch is believed to be one of only two survivors. (The other is a disc published in New York called Blender.) Thus, Launch is one of the only outlets for this form of advertising.

But that is likely to change. While the Internet now is not so much an Information Superhighway as a Data Deer Trail, the bandwidth limitations that are slowing traffic to a crawl will eventually be eliminated (even though experts say potential solutions, such as cable modems, are probably a lot further down the road than most people would like).

Thus, the interactive commercials seen on Launch might be a preview of what we'll eventually see a lot more of on the Internet.

The intriguing aspect of the ads on Launch is that they are designed to be as entertaining as the rest of the content on the disc. Computer users, unlike television viewers, are an active audience - which means they get to choose how to spend their time, rather than being forced to sit there and watch whatever a programmer broadcasts.

To reach people in an interactive medium, you have to design spots that people want to play with.

Do Launch subscribers actually spend time clicking through the advertising content? 2Way Media President Robert Roback says they do, and he has the stats to prove it.

Each issue of Launch - a bi-monthly magazine that is a sort of interactive Rolling Stone for the Generation X crowd, with interviews of rock stars and previews of movies and games - is equipped with tracking software that tells how long the user spends in each part of the disc.

Viewers are enticed with free tickets or other giveaways to complete a survey about themselves. When the viewer prints out the completed survey form, it includes encoded information about exactly where that viewer spent his or her time on the CD-ROM. That information is then decoded by 2Way Media, yielding a gold mine of details about what Launch subscribers view and for how long.

According to Roback, surveys have shown that users spend an average of five minutes cruising through the Butterfinger BB spot, as an example.

"We've had people who get a new issue of Launch and go straight to the Butterfinger ad, because it's so funny they just want to see if anything's new," Roback says.

This is tantamount to someone watching a TV show and actually asking to get a five-minute commercial.

On the Internet, most advertising content takes the form of banners - a rather boring-looking company name that invites users to click over to the advertiser's own Web site. Few advertisers are satisfied with banner performance.

"Of all the advertisers I've talked to, I would say that at least 90 percent realize those banners don't work. They're not interesting, and they're seen as a waste of time," says Roback. "You cannot force someone to look at an ad in this environment. You have to do something that really draws people in."

So if banner ads don't work, and animated interactive ads aren't feasible in the slow-motion environment of the Web, and CD-ROM magazines have only a limited circulation (Launch reaches about 150,000 people, through subscription, retail sales and bundling with computer products) - what's a savvy new-media advertiser to do?

Philip van Allen, whose Santa Monica-based Commotion New Media helped design the Butterfinger BB spot, thinks he has a compromise solution.

Commotion is working on interactive ads for the Internet. They don't have much animation, but they're more interesting than a banner - clicking on a character in a picture will, say, call up a funny thought bubble or something else that will make playing with the ad worthwhile.

"They'll be like our Butterfinger ads, in the sense that they will try to be entertaining. Whether they will be as rich as that, I doubt," van Allen says, "at least not for quite a while."