I recently started using dc(1), which is a reverse polish notation desk calculator with stacks every which way. It's not only fun, it's also very powerful (if you forget you can do basically the same in any other reasonnable language).
And anyway: RPN is essentially the same as PN, which is essentially the basis of the other other Ultimate Language (the Other Ultimate Language is Perl of course): Lisp. It should be pretty easy to convert any Lisp program to a dc program. So think twice before criticizing dc. Arrr.