AdBrite is offering a page takeover unit called "Intermission" that it hopes "makes more money for publishers, and gives more exposure to advertisers." Can't argue it'll succeed on both counts, at least in the short term. The ad essentially redirects users to an advertiser's Web site (example), which they must click through to get the content they really wanted.
The appeal for AdBrite is clear. High CPMs and no production required. It also happens to be over-the-top intrusive.