Edwin Bryant on the Yoga Sutras of Patanjali
This is an absolutely fantastic lecture on the Yoga Sutras of Patanjali and its relation to other religious developments in pre-modern India. Edwin Bryant is a professor of Indic Religions at Rutgers University.
Radhikaji on the Yoga Sutras
This is an extended lecture on the Yoga Sutras from Radhikaji, a yoga teacher based in Germany and India. Radhikaji, like Edwin Bryant, emphasizes the difference between studying the Sutras (and religion) as a practitioner vs. simply as an academic.