I have seen local TV listings for various PBS stations as late as 1976 that still showed some shows in B/W but I don't know if they were films from the 60s or then new stuff such as "Learning to play the piano".
There was a kids game show that Harrisonburg, VA's WVPT aired in 1980 called "Contact" ( Not 3-2-1 Contact ) and for some reason I remember seeing that show in B/W on a color set.
On a similar note, the very last TV show to air in B/W in all of TV ( commerical, non-commercial and cable ) may very well be the Rev. Donald Scruggs Guilding Light show which was seen on WINC cable ( Winchester, VA TV Cable ) channel 6 . I believe as late as 1989 ( yes 1989 ) was still in B/W despite the fact that everything else produced there had already switched to color many years before. Another show "Martha Hege", a 1985 clip of that program done by the same people is
available on You Tube, in color though.
From what I understand the reason behind this one show being in B/W is due to the host wanted that way and the only reason the show went color was that Adelphia took over the cable system.
Scruggs' show I think went off TV in 1995 or 1996. The man himself died not long afterward well into his 80s I believe.