Before I get any drops of jupiter hate on the following...I was typing in training.seobook.com & somehow accidentally hit enter after typing train & when the URL completion didn't work I got the following SERP.

If you click the feature video link it does a YouTube video overlay. The other links lead into the relevant iTunes webpage.

Such media extensions have been in place for movies for quite a while now, but this is the first time I have seen them on music-related search results. In time one could expect similar ad expansions to hit other media areas like books, games, and maybe even other vertical search features. Google could possibly roll it out globally on brand searches as well at some point, allowing companies to offer intro videos (or even reviews of new product lines) directly in the search results.