This book is definitely Pratchett's homage to William Shakespeare. Even while our three witches toil and trouble around their cauldron, Pratchett has filled this story with allusions to Shakespearean plays. He even goes so far to have a traveling theater troupe complete with in-house playwright. A theater is being constructed toward the end of the story that reminds me of the Globe and direct quotes from Shakespeare weave their way into the narrative. I mean, "the play's the thing" here just as it was in Hamlet. I love that among the actual plot of the book this whole second layer exists full of literary allusion to keep watch for.
But the actual plot...it's your typical medieval story with a murdered King (now a ghost), meddling witches, roving performers, and an heir hidden in order to keep him alive. The difference though is the humor. This typical story is infused with so much humor the plot really is immaterial. The cast of characters is pretty traditional - there's even a court jester - but the stars of the show are our three witches: Granny Weatherwax, Nanny Ogg, and Magrat. These complex ladies claim to never meddle in state affairs yet deftly manipulate time, space, and the strings of destiny for the entire kingdom of Lancre in order to bring the 'rightful' king to the throne. Expanding any further on the plot or the colorful cast of characters would almost give too much away, so I think I'll leave it at that.
I always laugh out loud when I read Pratchett. His wit and subtle humor and amazing control of the English language is a joy to read. And the extra perk of the Discworld books is that you don't have to read them in order to enjoy them - you can pick up whichever one you like whenever the mood strikes you. It's very nice to have such a stress-free series to read.