Despite the growth in number and popularity of collegiate a cappella ensembles in the USA over the past 20 years, few researchers have studied these self-governed, student-run, popular music ensembles. This ethnographic case study examined the music making and culture of the "Accafellows", an all-male a cappella group at a mid-western American university. An analysis of coded data from individual and group interviews and rehearsal and performance observations revealed five emergent themes: (1) music-making culture; (2) fraternity; (3) alumni involvement; (4) autonomy, leadership and hierarchy; and (5) value of participation. Findings provide a glimpse into the musical lives of the nine members of the group and shed light on the value of their participation in this music ensemble. On the basis of these findings, the author provides recommendations for music educators and suggests future research on informal music practices in formal settings. (Contains 1 table and 1 note.)