Cinco de Mayo Means Double The Halo 3 XP For Some Reason. This weekend leads into the Mexican holiday that commemorates the victory of General Ignacio Zaragoza Seguín over French forces in the Battle of Puebla, giving everyone else an excuse to get mucho sloshed on Coronas and margaritas. It also, for some strange reason, means that Halo 3 players will gain twice the experience in game with "Fiesta" style rule sets. As Bungie.net states "Cinco De Mayo requires both the Heroic and Legendary map packs for participation." Good times!