 Episodes are available online through YouTube.While episodes originally consist of a 6-week daily course, some stations air episodes on a less-frequent basis, as little as once a week.New York City PBS station Superstation WNET (operator of THIRTEEN, and its Sister Station and Network, WLIW 21 & NJTV, respectively) was the last PBS affiliate to air the show and aired it daily (sometimes twice daily) before pulling it from its lineup in 2009.