The de Yoyos are a noble family from Pseudopolis, whose scions have long been associated with intrigue and adventure, supplying the Disc with many notable explorers and adventurers who have 'discovered' many otherwise-unknown areas (known only to natives, peasants and others who simply do not count on the basis that they are not from the "civilised" world, similar to Roundworld, where America and Australia were "discovered" whilst being happily inhabited by their own native peoples. This paradox leads Lord Vetinari to propose the establishment of the Trespassers' Society.
The current Kompt ("Count" in Morporkian, also spelled Compte) is one such mysterious and adventurous, travelling sort: spotted at the Samedi Nuit Mort Ball in Genua as a guest, he is currently the Lecturer in Modern Languages and Music at the Assassins' Guild School. He is a member of the Assassins' Guild and it is said that his favourite pass time is hanging, by one hand, from high buildings.
The famous explorer Guy de Yoyo was a previous Kompt de Yoyo. He discovered the Disc's second-highest waterfall in the Year of the Revolving Crab. Of course, lots of dwarfs, trolls, native people, trappers, hunters, and the merely badly lost had discovered it on an almost daily basis for thousands of years. But they weren’t explorers and didn’t count.
The dyslexic artist Don Weizen de Yoyo is also a family member.