"Rocky V" is the nickname for the popular Super Bowl XLII commcercial for Budweiser. Seeing how there has not yet been a seventh installment of the series the ad has inherited the spot (not to say that a future Rocky film won't be named the same).
The summary of the commercial is that a Clydesdale (the specific type of horses that Budweiser uses in ads recently who represents Rocky since Rocky is nicknamed the Italian Stallion) isn't selected to pull the iconic Budweiser wagon. Naturally, the horse is dissapointed yet is uplifted by the influence of a dalmation who represents Apollo Creed. The dalmation trains the horse (a la Rocky IV where the horse runs through the snow like Rocky in Siberia) and the horse makes the crew at the next tryouts for a spot on the wagon's team. The commercial ends with a sarcastic pound of the horse's hoof to the dalmation's paw.
Person 1: What was your favorite commercial this year?
Person 2: I liked Audi with "The Godfather Part IV".
Person 1: I'd go with Budweiser and Rocky VII.