For many youth, afterschool programs positively fill the time between school and home. Quality out-of-school time (OST) programs clearly can have beneficial social and academic effects on youth (Durlak, Weissberg, & Pachan, 2010; Eccles, Barber, Stone, & Hunt, 2003; Vandell et al., 2005). However, these outcomes are not guaranteed (Chen & Harklau, 2017; Eccles et al., 2003). Realizing the potential for improved social and academic outcomes depends at least in part on the ways in which afterschool programs are structured. At the most basic level, in order to gain the potential benefits of afterschool programming, young people must participate. One common strategy is to structure program activities so that they build, over a semester or a year, to a culminating end product. Larson (2000) and Heath (2001) have referred to this pattern as a "temporal arc." This article is based on a yearlong ethnographic study, consisting of over 240 hours of participant-observations during the 2015-2016 school year.