In Iron Man, Tony Stark (Robert Downey Jr.) is driving an Audi car. The car brand is promoting its image through the Iron Man movie.
Audi is even using a comparison between the car and Iron Man's armor to promote its cars in two promo spots in which one may may see some footage from the upcoming superhero movie:
Audi cars are as fast as Iron Man! (Please drive slowly though...)
And Audi cars, like Iron Man, are the products of intensive research in design and engineering!
I must admit that those two spots are really well done! Especially the second one which my favorite. If I had a driving licence I would buy one such car right away! After all it's Iron Man's car! (for now I'll make do with the subway...)