The first amendment of the constitution forbids impeding the free exercise of religion, and the military is no exception. Sundays at basic training are the days you can attend religious services. I suggest if you are not religious, you get religious. You should plan on attending services, even if you are not religious or spiritual in any way. It is a great break from a drill sergeant. If you don't attend, the drill sergeants are going to find something for you to do. and it won't be as fun as attending religious services. When I attended basic training the recruits marched twenty minutes through the snow just to get to the religious services. Uphill, both ways too. We were glad after a hard week's work to attend the religious services as well. If you are not religious, respect your surroundings and the people around you. Don't talk, don't write letters, and don't do other chores, or try to make friends. Just about every religion can be accommodated for, so use your time at basic training to exercise your body and your spirituality.