Grass is a documentary narrated by Woody Harrelson that came out in 1999. This documentary chronicles the history of the social perceptions of Marijuana and Marijuana laws in the United States.
The most fascinating aspect of this documentary is how it illustrates how Marijuana Laws changed based on who was using the drug. For example, when the majority of people prosecuted for marijuana possession were minority group members the penalty for possession was around 50 years in prison. However, when a White war hero was caught selling Marijuana and got a 50 year jail sentence there was a huge public outcry, which ultimately resulted in the penalty for possession being lessened. This is a poignant example of racial inequality in the implementation of laws.
To read a more detailed summary check out this link from IMDb http://www.imdb.com/title/tt0214730/plotsummary