A tasty morsel from the Buddhism MOOC, offered right after the famous "tolle, lege!" scene from Augustine's Confessions. It's from the autobiography of the famous Thai forest monk Phra Ajaan Lee (1907-61):
I was very ardent in my efforts to practice meditation that rainy season, but there were times I couldn’t help feeling a little discouraged because all my teachers had left me. Occasionally I’d think of disrobing [ie leaving the monastic order], but whenever I felt this way there’d always be something to bring me back to my senses. One day, for instance, at about five in the evening, I was doing walking meditation but my thoughts had strayed towards worldly matters. A woman happened to walk past the monastery, improvising a song—‘I’ve seen the heart of the tyd tyy bird: Its mouth is singing, tyd tyy, tyd tyy, but its heart is out looking for crabs’—so I memorized her song and repeated it over and over, telling myself, ‘It’s you she’s singing about. Here you are, a monk, trying to develop some virtue inside yourself, and yet you let your heart go looking for worldly matters.’ I felt ashamed of myself. I decided that I’d have to bring my heart in line with the fact that I was a monk if I didn’t want the woman’s song to apply to me. The whole incident thus turned into Dhamma.
I was very ardent in my efforts to practice meditation that rainy season, but there were times I couldn’t help feeling a little discouraged because all my teachers had left me. Occasionally I’d think of disrobing [ie leaving the monastic order], but whenever I felt this way there’d always be something to bring me back to my senses. One day, for instance, at about five in the evening, I was doing walking meditation but my thoughts had strayed towards worldly matters. A woman happened to walk past the monastery, improvising a song—‘I’ve seen the heart of the tyd tyy bird: Its mouth is singing, tyd tyy, tyd tyy, but its heart is out looking for crabs’—so I memorized her song and repeated it over and over, telling myself, ‘It’s you she’s singing about. Here you are, a monk, trying to develop some virtue inside yourself, and yet you let your heart go looking for worldly matters.’ I felt ashamed of myself. I decided that I’d have to bring my heart in line with the fact that I was a monk if I didn’t want the woman’s song to apply to me. The whole incident thus turned into Dhamma.
The Autobiography of Phra Ajaan Lee, trans. Thanissaro Bhikkhu, 9-10