There are a few movies I can note where their directors also played a role in their films. Orson Welles tended to star in many of his films, but that was during the 40's. Roman Polanski played the role of the man who cut Jack Nicholson's nose in Chinatown, but Chinatown was released in 1974. The most recent film I can think of where this happened was when Quentin Tarrantinto played Jimmy in Pulp Fiction, which was released in 1994.
I can't really think of any recent movies where directors did this. Is it common to see directors acting in their own films these days?