In what social settings can i wear sweatpants in?

A good pair of sweatpants, especially Notre Dame ones, is appropriate AT ANY TIME! So long as they are not overly tight and you do not have a side-part. They look particularly good with ratty t-shirts with holes in the arm-pit. You might also pair them with a on-down collared shirt, to achieve a look that is, what I like to refer to as "The Mullet of Fashions."