Not so much a Discworld story as a story that uses Discworld as a framing device. This is in its essence a Bildungsroman where the hero becomes an assassin (of sorts) and returns home to assume kingship of a nation imprisoned by religion. He requires his cutthroat education to survive.

The story also includes a Star Wars vignette. For more literary references: (there are spoilers)

http://wiki.lspace.org/mediawiki/Book:Pyramids/Annotations

And Terry Pratchett did this will all the deft skill and comic timing that is his trademark. Teppic's encounter with the Sphinx could be a Python skit.

Great fun!