I have a confession to make. I've been designing programming languages since I was nine years old (the very first was syntactic sugar for 8085 assembler). Most of them have never been observed in the wild, but one seems to have escaped and taken on a life of its own. Now, I find that there's an implementation of "99 bottles of beer" in it, as well as an interpreter written in OCaml.
I am no longer excited by Io; continuations seemed a lot more interesting when I was a teenager than now, although it is of course useful to know how to program with inverted flow of control. It is, perhaps, a useful illustration that continuations, like a number of other language primitives, are powerful enough that you can build an entire programming language from them and nothing else.
Also, I enjoyed chromatic's essay What I Hate About Your Programming Language. I tried responding on the comment page, but it wouldn't take my login. I'm sure the login problem is due to the website being written in some dynamic language that encourages messing with stuff, rather than good ol' C, which requires you to think through what you want the code to do first.
Seriously, while chromatic's mention of mod_virgule as a website written in C is gratifying, if I had to do it from scratch, I probably would use Python. I like programming in C (especially deep algorithms), and I like programming in Python (especially prototypes, and gluing things together).