Sony is holding a Double XP Weekend for Killzone 3’ players in celebration of the return of online to PSN. It is running right now, and will cease on May 23 at 10:00 am UK time. Of note: during the Double XP Weekend, the Score Screen will display the message “Fast Starter Bonus” instead of “Bonus Points” – this is a string error that will be fixed in future Bonus XP events. Get more information through the link. You can also earn Double XP with Black Ops on the PS3 this weekend as well.