[muraiki]

I really liked the following article, which creates a text adventure language in Racket that looks like this:

  ===PLACES===
  ---desert---
  "You're  in a desert."
   [cactus, key]
  north    start
  south    desert

http://queue.acm.org/detail.cfm?id=2068896

[shriramkmurthi]

Scribble is another great example. It's amazing in its own right, and by being embedded into Racket, gets all the Racket benefits: for instance, separate compilation! (Thirty years and waiting, LaTeX.)