Small Gods by Terry Pratchet
Book Description
Lost in the chill deeps of space between the galaxies, it sails on forever, a flat, circular world carried on the back of a giant turtle--
DISCWORLD
--a land where the unexpected can be expected. Where the strangest things happen to the nicest people. Like Brutha, a simple lad who only wants to tend his melon patch. Until one day he hears the voice of a god calling his name. A small god, to be sure. But bossy as Hell.