I once read a book about a group of people who discovered a hidden temple city in a mountain range, where the Incas-the ancient civilisation of Peru- had fled to when the spanish invaded. When this group found the burial chamber of one of the inca high priests, they unleashed a powerful curse upon them all...
Somehow, someway, a band of gnomes learns how to be ninjas. In fine gnomish style, they open an academy to teach this art to other gnomes. Wacky Hijinks ensue. Or the gnomes become some of the finest assassins in the land. Or both.