The Scheme Programming Language
Scheme is a nice dialect of Lisp, which is a computer programming language that was first implemented in 1958. This doesn't make it the oldest programming language by any means, but it is well-established.

After working with it a bit, I think I can see why some people love it and others dread it. It bears almost no resemblence at all to any of the other languages that I have worked with over the years. There are no gotos, for loops, while loops, etc. Any looping has to be done using recursion. In fact, while I was programming in Scheme, I felt at several times as though my mind was being twisted into a pretzel. I'm sure that those who adapt to this way of thinking can get to enjoy it. There are a lot of things to like. I'm just ready to devote my life to it right now. I have to say, though, that my brief experience was worth it.