If you've seen Iron Man enough, you might have caught the Burger King product placement.
While product placement isn't exactly a rarity anymore (in fact, it's only going to increase in movies in the coming years), the deal to have Burger King in Iron Man was actually spawned because of how it saved Robert Downey Jr.'s life.
According to RDJ, in 2003 he was driving a car full of drugs when he decided to go grab a burger.
The burger he had was, apparently, exceptionally disgusting. So repulsive was the burger that he thought something really bad was going to happen.
It made him rethink where his life was going, and so he drove down to the ocean and threw all the drugs that were in his car into it.
From that point forward, he started recovering from his drug use. Of course for Burger King it's a bit of a double edged sword, because though it's advertisement by a celebrity, a "horrible burger" doesn't really resonate that well with people.