There's a theory that the medieval tournament (jousting, etc.) arose because rulers wanted to make sure that (a) their aristocracy was prepared for war, but (b) as it's really difficult to distinguish war game preparations (large gatherings of armed and provisioned knights) from rebellion preparations, the formal tournament —announced well in advance, with a recorded list of participants— meant an aristocracy kept busy by the former had no free time for the latter.
(a little like the principle that one should encourage one's sales force to take up expensive hobbies and acquisitions: keeping them hungry for the next commission)
