These are a whole list of organizations, which are primarily located in the United States - called "appendant bodies". The most famous ones are:
York Rite
Scottish Rite
Shriners
Eastern Star
There are many others, including the Grotto, Lodges of Research and so on and so forth. Most require status as a Master Mason.
York Rite, in very (very) general terms represents the Christian arm of American Freemasonry. That is a terrible over generalization, but it is the group most frequently associated with "Knights Templar".
Scottish Rite, like York Rite, is often called the "University" of Freemasonry. It is where you can become a 32nd and 33rd degree. It focuses on many faiths and philosophies.
The Shrine is more "fraternal" in that they have many social activities, and many of the men who are active there are married folks who involve their better halves in Shrine activities. They are well known for their hospitals and little red cars in parades.
The Eastern Star is a co-ed organization, largely run by the ladies of Freemasons.
These are all really terrible generalizations. Ones that would require clarification and far, far longer explanations to really get to the heart of.
And all of it is based on Blue Lodge, which is the center of it all and the most important by a long, long way.
I would recommend a book "Freemasons for Dummies". As strange as it sounds, I've found that book, which was written by a Freemason who has visited the lodge I was raised at, to be a pretty good overall source. It gives better explanations of some of these "appendant bodies" than I am giving here and may give you a bit of an outlet for your curiosity - which we have all shared in your shoes.
http://www.amazon.com/Freemasons-Du...470551&sr=1-1&keywords=freemasons+for+dummies
If you are accepted into the Fraternity, directly after initiation you will have plenty to keep you busy.
This is going to sound really strange, but the other thing I would suggest studying in your shoes would be cooking. Men at a lodge love a candidate with skills at that, for well and true. This book rocks, and is appropriately named "Low and Slow":
http://www.amazon.com/Low-Slow-Master-Barbecue-Lessons/dp/0762436093
