The goal of advergaming is to encourage consumers to engage in a branded experience--that is, spend time voluntarily with an ad. That is usually more efficient and effective for a marketer than to chase after consumers with ads they are likely to shun. Among the other brands that have added sponsored online games to their marketing tactics are Jeep and Life Savers.

One "huge risk" in advergaming is that sponsors may "become better known for the games" than for their products or services, said Henry Harteveldt, an analyst who is the vice president for travel research at Forrester Research. Orbitz provided Harteveldt an advance look at the Web site so that he could discuss it with a reporter.

Advergaming that is done well "strikes a good balance between being creative and different," Harteveldt said, "and making sure people know who's behind it." He praised Orbitz for making "the brand part of the URL," or Web address. By contrast, some advertisers offer games under names like the Life Savers Web site, called candystand.com.

Orbitz executives have been mulling for some time ways to give computer users regular access to its online games. They first appeared in the form of what are called pop-under ads, that is, banner ads that turn up on a computer screen after a Web site is visited. Many computer users consider such ads annoying and have installed blockers that screen out pop-unders and their counterparts, pop-up ads.