Student motivation in higher education is a popular topic, though there is virtually nothing known about how motivation changes over the week. Based on observations of student behaviour in the classroom and considering popularly used expressions in everyday life (e.g. TGIF, Motivation Monday), we investigated how motivation changed over the week and patterns that repeated weekly. Data were collected from undergraduate students over 56 consecutive days to allow detection of motivation cycles and fit trigonometric functions to the data via spectral analysis. We also examined how mood and motivation covaried over the week. Our results indicated: (1) motivation follows a cosine function with a weekly cycle -- motivation begins to increase on Sunday and is relatively high early-week, tapers off on Friday, and is lowest on Saturday; (2) weekly cycles of mood; and (3) cyclical covariation between mood and motivation. Implications for research, students, and universities are discussed.