Jon Purdy on concatenative programming, which I had never heard of before. Basically it is purer functional programming for those of you who think Haskell is too corporate. (Actually, I enjoyed the read.)
P.S. — A remark from a clever fellow, no slouch he: That made my head hurt and reminded me of, when I was a freshman, trying to do a few chapters of Abelson & Sussman on my HP 28S calculator, which had RPN and (I realized) first-class functions.. I miss RPN calculators.