The Colour of Magic (2008)

The Discworld - a magical realm quite unlike, yet hauntingly familiar to, ours - has got it's first tourist. Rincewind (David Jason), an inept ex-student wizard is given the task of guiding Twoflower (Sean Astin) through the city state of Ankh Morpork. Rincewind has two problems: firstly, as an expert coward, he doesn't feel he's the best person to guard a naive - and extremely rich, by local standards - tourist through one of the roughest cities in the multiverse. And secondly, the world is coming to an end. Never rains, eh? The film of The Colour of Magic combines Terry Pratchett's best-selling fantasy novels The Colour of Magic and The Light Fantastic.
Oh, and a well-known author appears in a cameo role! [imdb]