I am working in call centre as trainer on american culture and the festivals, have good knowledge about it, but would like to know a lot more about it.

You'll get a better response if you pose a few topic-related specific questions here.

You need to be more specific...
What are you looking for, exactly?

American culture? Is there any such thing anymore? American culture is such a blend of all different cultures. Festivals can be Renaissance, Traders & Trappers, Scottish, Mexican, Cajun, etc. and they are all American.

So focus on something specific and you might find a better answer.

The Culture of the United States is a Western culture, and has been developing since long before the United States became a country. Today the United States is a diverse and multi-cultural nation.

Its chief early influence was British culture, due to colonial ties with the British that spread the English language, legal system and other cultural inheritances. Other important influences came from other parts of Europe, especially countries from which large numbers immigrated such as Ireland, Germany, Poland, and Italy; the Native American peoples; Africa, especially the western part, from which came the ancestors of most African Americans; and young groups of immigrants. American culture also has shared influence on the cultures of its neighbors in the New World.

http://en.wikipedia.org/wiki/Culture_of_the_United_States

http://en.wikipedia.org/wiki/Category:American_culture

You can go through this list:

http://www.search.com/search?q=American+culture+and+festivals

http://mamma.com/Mamma?utfout=1&qtype=0&query=American+culture+and+festivals&Submit=%C2%A0%C2%A0Search%C2%A0%C2%A0