There are many examples of Afghan culture and tradition in this story. Part of the sadness of the story is that we see how the culture has suffered from the disruptions of war and politics, and part of the happiness of the story rests on our seeing the preservation of Afghan culture in the new world of the United States.
One example of this is the kite racing that figures so prominently in the book. Amir tells us that "The kite-fighting tournament was an old winter tradition in Afghanistan (51). Although the Taliban do away with kite racing, at the end of The Kite Runner, we see that this tradition has been preserved within the Afghan community in America, and that it is this tradition, in fact, that begins a process of healing for Sohrab.
Other examples of Afghan tradition are the customs associated with Afghan marriage. These are clearly preserved in the United States in the Afghan community. We see this as we watch Amir and Soraya court and fall in love. Baba must see Soraya's father to ask for Soraya's hand in marriage to Amir. A gathering follows the General's consent, called "lafz," which means "giving word (167.) When the General and Amir meet at the this gathering, Amir tells us,
"The general held me at arm's length and smiled knowingly, as if saying, 'Now, this is the right way - the Afghan way - to do it, hachem.' We kissed three times on the cheek" (167).
There are speeches and ceremonies at this gathering that are clearly traditionally Afghan. Other traditions are set aside because Baba is dying, and the couple wants to be wed before he does so. But the wedding itself is a traditional Afghan wedding held in an Afghan banquet hall. The wedding is described in detail on pages 170 and 171.
We do see other glimpses of Afghan culture throughout the book, in the descriptions of Baba's house, for example, and in references to the kinds of foods Afghan people grow and enjoy. Afghan culture is rich and fascinating, and I have provided you with a link to a web site with more information about it.