Vincent, these are all very good questions and I'm sure that most of us could write a book about what we know of the fraternity/sorority system. Most of the organizations are national and/or international in scope with chatpers established at colleges and universities across the county.
Most undergraduates tend to view their experience on a local leve since that's all they may ever see of their organization. Once you become an alumni, or move to another part of the state/country many people meet other members from other chapters and gain more understanding about thier organization on a broader level.
Relationships between different chapters on a campus vary, but in most cases Greeks work together for mutual benefit and are self governing. Each campus typically has some sort of Fraternity and Sorority council to address issues and promote unity and good working relationships.
There are many student organizations and opportunities for leadership on campus, but Greeks promote leadership within their organizations and other campus organizations and are typically some of the most involved undergraduates in other campus organizations. Most Greeks are very devoted to the success of their chapters, but also get involved in many other groups.
Some campuses have a high percentage of students who are Greek, while others are more moderate or small. The area of the county also depends on how popular Greek life is on campus. For example, universities in the Southern part of the US typcially have very large, well established Greek systems where a high number of students participate.
Not all campuses have the traditional houses, but generally there is some sort of housing or facility available in a dormitory where Greeks can have a common living experience if there are no houses.
In general, men's houses are more likely to allow alcohol and parties on the premises while all women's groups prohibit alcohol in the house. Women still have meetings and other functions in their houses, but they are dry events.
I am not sure what you mean about Fraternities being mixed. Do you mean gender or race? Most (99.9%) national groups are exclusively men or women. Most groups do not discriminate on the basis of race, but the number of minority members of chapters varies depending on where in the US the chapters are located.
Lastly, most people join Greek organizations as an undergraduate. However, there are some women's groups that initiate graduates. The exception to this rule is with the Historically Black (African-American) Greek Organizations (HBGLOs). I believe that just as many graduates as undergraduates join these organizations. I cannot speak for the men's groups, since I am not sure how many of them allow for alumni initiation. My sorority does not allow for alumni initiation except in very rare circumstances, so I do not know that much about it.
All of the Greek organizations provide a lifetime membership and opportunities for alumni involvement. While I love my university dearly, I would probably not have as close ties as I do if not for my Greek membership. With the exception of football in the fall, my primary bond and affection is my Greek membership and the relationships and other organizations I became a part of solely because I was Greek.
There are some elements of Greek Life in the movies that are truthful, but in general they are very stereotypical of Greeks. For example, I know I attended many fun parties that could be compared to the toga party in Animal House, but this was not the primary focus of my membership. The sense of sisterhood, belonging, and the focus on leadership and developing skills that would serve me well after college were much more important than any party I could have attended. Social events are a fun aspect of Greek life, but it is only a part of that life and does not take the place of the opportunity for lifetime membership, strong friendships, and service to others.
Personally, my favorite Greek 'movie' is Legally Blonde. I think that the ability to lead and work together in a same-sex environment builds the confidence to lead and be successful in the 'real world' after college. It showcased a built in support system where people share your successes and cry with you in your disappointments.
You might also want to check out the website for the National Panhellinic Conference at
www.npcwomen.org. The NPC is the umbrella organization for the 26 (historically white) national women's groups. The website has links to all 26 organization home pages.
Hope this is helpful. Good luck!
