Casters have long used magic to settle their disputes, often with disastrous effects. Over the years, these duels developed into the codified contest of skill and cunning that we have today: the Duel of Wands.
In Duel of Wands, which is set in the world of the Kids on Brooms RPG and which contains rules for use within that game, players attempt to prove themselves the superior caster by slinging spells at each other to try to remove their opponent's psyche and win the duel. Don't grow too confident in victory because between rounds, the loser can study and improve their spells!