Which comedy movie was Will Ferrell's breakthrough as an actor?

Explanation

Will Ferrell is a well-known name on the American comedy scene. He started out as a stand-up comedian, but quickly broke through as an actor in the movie "A Night at the Roxbury". Since then he has featured in countless comedies, some more highbrow than others. For instance, he has featured in four movies directed by Adam McCay, the no. 1 American comedy director. Ferrell has had a few dramatic roles, e.g. in the magical realist "Stranger Than Fiction" and especially in the Woody Allen movie "Melinda & Melinda".