Some of Apple's patents become real products, but many more don't. So who knows if the "visual or audible" ads described in a newly unearthed 2008 patent application will ever see the light of day. Check out the description:
Among other disclosures, an operating system presents one or more advertisements to a user and disables one or more functions while the advertisement is being presented. At the end of the advertisement, the operating system again enables the function(s). The advertisement can be visual or audible. The presentation of the advertisement(s) can be made as part of an approach where the user obtains a good or service, such as the operating system, for free or at reduced cost.
The advertisement could appear as: - a pane on top of any other pane in a user interface of the device - in a designated area of a background of the user interface - in a window for an application program - inserted in content from an application program - through an audio output of the device; and combinations thereof.