I was reading an article about implementing an interpreter for Brainfuck in PyPy, and when the example code for some simple Brainfuck programs came up, I just stared. I really fail to see how one would go about programming just about anything in that language. (Here's the article in case anyone is interested, a pretty good read IMO: http://morepypy.blogspot.com/2011/04/tutorial-writing-interp...)
Besides a gotcha with weird bugs when I called the superclass dealloc method before releasing members, I had a really smooth experience.