It's (funnily) referred to in the Q&A after his 2012 PyCon talk: https://www.youtube.com/watch?v=R9ITLdmfdLI&t=47m
Essay on 2003 talk: https://news.ycombinator.com/item?id=20357995
Past HN post about 2012 talk: https://news.ycombinator.com/item?id=3690106
Essay on 2012 talk: https://paulgraham.com/ambitious.html