Robert Downey Jr. is basically the embodiment of the Marvel Cinematic Universe. There may be no line which more perfectly set the tone for what the Marvel Cinematic Universe would grow to become than Tony Stark announcing to the world in 2008, "I am Iron Man." That original line, amongst many others, was improvised by Downey on the spot.
Downey was practically given free rein to explore Stark's dialogue in each film, and many of the improvised lines ended up being some of the most memorable. Take a look below and vote up the best improvised Iron Man quotes!