Hungry for White Castle?

Although I have not seen it yet, my younger brother has seen the new Harold and Kumar Christmas movie. I've always been somewhat fascinated by the the trilogy of the movies because it was made almost entirely as an ad campaign for White Castle. I can't think of any other movie that was based solely on one product, I'm sure there are other movies that are based heavily on one product or idea; however, I can not think of any others at this moment. I do believe that Harold and Kumar is one of the most well known movies of all of time that is based off of an ad campaign, and since the first one they have been able to make two more movies. Neither one is related to White Castle the premises are different but, when everyone thinks of Harold and Kumar they automatically think of White Castle, so there is subconscious advertisement going on just because the name is so associated with White Castle already.