Specifically, they're iPod ads, and they are standard Mac white with bright images of the product being played with, and minimal text. In fact, the only text is either 'iPod Touch' or:
|"The funnest iPod ever."|
Maybe it's my pro-mac bias coming out, but I think this is a particularly pithy, appropriate and communicative Invented Usage.
Because it's the only text in all the ads throughout the station, we can't possibly think that 'funnest' is an error or is unconsidered. Further evidence that it is a conscious choice comes from the fact that it matches the content of the ads: 'funnest' is a fun word. At least, it's certainly more fun than 'most fun'.
I am generally a fan of language that does what it talks about, or imitates the experience it tries to convey. 'Funnest' is a nice clean example of this. Writing teachers are fond of saying, 'show; don't tell'. And 'funnest' does both in one word.