At least 50 TV theme songs have hit the charts ... Lovin’ Spoonful frontman John Sebastian wrote and recorded the Welcome Back, Kotter theme, hitting No. 1 on the Billboard Hot 100 chart ...

Back in the seventies ... Spend an hour or two - or a full four seasons - in Mr. Kotter's classroom again, joining in the antics and reminiscing about wiseguy teachers and goofball high schoolers.