Ready to celebrate Cinco De Mayo the bungie way?  Well, if you own boths Legendary and Heroic Map Packs, get ready to earn double EXP all weekend through Tuesday May 6th.  The game type is Fiesta (throwback to Halo 2), and everytime you spawn, you have random weapons.   Don't have the map packs, get the Legendary map pack for free and be prepared to shell out 800 points for Heroic map pack.  So put down the GTAIV and CoD4 and get your Halo 3 on!  Official word from bungie can be found here.