Here is a page of Japanese Nintendo DS advertisements. It appears that in Japan you can buy PDA-style software for the DS, with useful functions like translating languages or being delightful in other, more inscrutable ways.
Then there are the Hot Mario Bros. commercials, which are somehow not as wonderful as you would expect.
The anime-style Max Devilpower looks pretty awesome for a sports game. Is that ever coming here?
I'm not sure I've ever seen a commecial that spotlights gameplay in this much detail.