In the late 80's I worked at a radio station that played these shows. That was my job as a part-timer on the weekend, to swap out tapes and play them on the air and this was one of the programs. Fantastic show, although I haven't listened to it in a long time. My 14 year old daughter has some Oddysey CD's and she used to play them all the time but has since outgrown them.
Trivia: Whit was played by "Otis" Hal Smith until his death:
Great shows all around, good fun. My favorite were the time travelling episodes. There's probably hundreds and hundreds of episodes. It started in 1987. Dave Madden (Rueben Kincaid on Partridge Family) was also a character on the show for many years.
There is also an Oddysey cartoon but I don't know if it still comes on.
You can learn more about it here:
I heard another great "older audience" radio show called "Just South Of Normal". It was fantastic as well and geared towards teens. However, I do not think it lasted very long at all. I only heard a couple of episodes and then it disappeared and this may have been around 2002 or so when I heard it so it was quite some time ago.