I watched To Sir, With Love last night; I thought it was far from great film-making, but fairly enjoyable. Sidney Poitier was rather good in it.
For a lot of the film, though, I thought 'Surely this screenplay was adapted from a play.' When I looked it up at the end, I found it wasn't - but then that a large number of the cast had originally been trained for the stage. It's funny how distinct these things are, isn't it.