Sean Penn turns 52 on Aug. 17, 2012. The actor, screenwriter and film director is known for his roles in films such as &#39;Fast Times at Ridgemont High,&#39; &#39;Mystic River&#39; and &#39;Milk.&#39;&#40;Pictured: Sean Penn appears in a scene from the 2008 film &#39;Milk.&#39;&#41; <span class=meta>(Focus Features &#47; Axon Films)</span>