Interesting Times by Terry Pratchett

Set in the Discworld version of China (the Aurient, for land of gold!) at the time of a rebellion by the 'Red Army'. Rincewind the wizard is sent there by the other wizards by order of a Auriental lord. The rebels think he is a Great Wizard (how wrong they are) and he spends most of the book hilariously trying to run away. Then he learns to activate the real Red Army (predictably made of terracotta clay) and defeats the corrupt lords. Throw in Cohen the Barbarian and his Silver Horde and you have a brilliant book.
"They have a curse. They say,'May you live in interesting times.'"
I have a blessing. I say, 'May you read interesting books.