Though no one is quite sure what it is going to be yet, the Rally to Restore Sanity, organized by the comedian Jon Stewart and set for Oct. 30 on the National Mall in Washington, is drawing widespread national attention.

Most national news organizations have made requests for credentials to cover the event, and almost 300,000 people have so far signed up to attend. What Mr. Stewart’s cable network, Comedy Central, is labeling “satellite rallies” have been scheduled in more than 40 locations nationally and at least six foreign countries.

And all of this has taken shape despite a minimal publicity effort from Comedy Central, beyond announcements of some details by Mr. Stewart and his colleague, Stephen Colbert, on their late-night shows, and information doled out on Web sites created for the event.

News organizations have no idea whether the event is meant to be political or entertaining in nature, but most of them, including CNN, MSNBC, Fox News and the three network evening newscasts, have plans to cover at least some portion of the rally live.