If you are not interested in discussing religion with someone, simply thank them for their interest and excuse yourself.
Separation of church and state is a key concept in American government and culture. The first line of the First Amendment of the United States constitution states that church and state are to be kept forever separate. On this basis, the former custom of allowing prayers in public schools, even if non-denominational, has been discontinued.
For those of you who are Muslim, there is a Mosque within walking distance of the University of South Carolina campus. EPI does not have classes on Friday afternoons so that students have free time for their own activities.
Link to Mosque Website
There are also a number of churches and temples in town.
Link to Church/Temple listings