Moving Pictures is the tenth novel in Pratchett's acclaimed Discworld series. It's hard to categorize within the Discworld canon, it can be considered part of the Rincewind/Unseen University stories. Yet the main characters, other than Gaspode the Wonder Dog don't recur in the later Discworld volumes. This would also be the first time in those stories where Rincewind doesn't appear.
The supporting cast is familiar and well loved, C.M.O.T Dibbler, the Patrician and Death appear and, in Dibbler's case, attempts to sell the show he has just stolen. The faculty of the Unseen University is being to assume it's mature identity. Mustrum Ridcully makes his appearance as the Archchancellor, although in a less polished incarnation. This event ended the oft alluded to, and occasionally seen, practice of succession to that position "via the dead man's pointy shoes." The Bursar is beginning to have his nervous breakdown and the rest of the faculty has been reduced from personal names to titles. The wizards have also gone from devious and scheming to fat and comic. The Patrician seems to have slimmed down from his corpulence in the Colour of Magic towards Vetinari's spare frame.
The story hits more memes from Hollywood than I can enumerate, the downside of them is that they leave me with a vague sense that the story was pieced together to around them rather than naturally including them.
The basic plot is saving the world from creatures with out. In Discworld reality is always under siege by "creatures from the Dungeon Dimensions", Moving Pictures has some very evocative scenes of these creatures intruding. It's a good chance to break out the "Random Creatures from the Lower Planes" tables in the back of the 1e DMG.
The description of the "Cthinema" under the hill, with it's screen like a pool of quicksilver turned on edge and seats full of undead would make an off beat mystery for players.
The effects of the clicks on the local population, it's easy to stop a villain, but how do you stop an idea? Is there a hidden mastermind behind the fad sweeping the area, or is it the fad itself that's contagious?
The idea that an unknown force is granting sentience to individual animals, is this where familiars come from?
Dead man's pointy shoes - the PCs must either take out a high level wizard for their patron to advance or protect their patron from assassination.
Plot: Read the book, it's Discworld, you'll enjoy it.