I just realized that one obvious place for full page advertisement is the 404 page.  All of us runs into them and when we do, we pause for a second or two at least to stare at the 404 page mindlessly.  Whole damn page is there and waiting to be stared at and puzzled over.  Why not tell the folks that Miller Light tastes great as well as less filling?  It shouldn't be too hard to hook up web servers in the world to redirect on 404.  Surely, this is more respectable than tatooing Apple logo on your forehead!