Roles are expected behaviors and actions of people within social situations and social settings. There are different roles for every social setting such as the role of a mother, sister, brother within the setting of the home, or the role of a student at college. When you are in these roles certain behaviors are expected of you.
In the documentary 30 Days, people are taken out of their normal lifestyle and put into different roles, which they have to live for 30 days. There are several different episodes portraying different situations and different lifestyles people are put into. The social settings are completely different and they are expected to fill these different roles. Link: http://www.imdb.com/title/tt0437696/
The basic idea of roles is portrayed very well within the documentary 30 Days. It shows how roles make up our society and how people try and fit the roles in which they are placed.