From March 2008 to October 2010, a playlist called the Double EXP Weekend was open for Halo 3 players with gametypes that aren't normally available for other matches on usual weekdays. Each win gives 2 EXP points, and a loss will not take away EXP. By far, the most featured playlist is the Grifball playlist, including slightly different arenas, and different leagues.
In some of the early Double EXP Weekends, Bungie made the mistake of making the ball-carrier gold instead of orange, resulting in the ball carrier becoming Grif's sister, Kakaina. This was corrected in subsequent updates.