Allow a person to enter a group for a 'quest'. Minimum amount of 5 since this way it means team work may be necessary. Allow a prize after completion of the quest.
Quest Ideas: (No Killing Quests Since it will result in a lot of laming) Capture 100 Bases within 1 week, Win 20 Iricia Games Within 1week and so on
Prizes: Access to a special gun, Ability to use a special class.
E.g. <Account>, <Account>, <Account>, <Account>, <Account> To Do <Quest name>
This idea can be incorporated into community guilds rather then groups.
As well as prizes can be edited and Quests can be altered if to simple.
Also if you can get this done by Easter you can do a group Easter Egg hunt
Have a Easter bunny appear at random every hour to drop a egg on a certain planet and have people search for it.
You can do the Idea above (about Easter) in a way that the person who finds the most Easter eggs gets a chocolate gun
which is like love rifle but heals more. (Doesn't have to be a chocolate gun)