Guess the monster
GM transforms into a monster and players have to guess its name. Each player that says the proper name of the monster gets +X credits and there is X rounds of the event.
Kill the GM
GM gets full reflect set, maximum health and anything that'd make him hard but fair to kill and sits at X city in easily reachable place. Players have to kill him in order to win the event, whoever kills him wins +X credits. (now depending on the players that are online and on how tanky the GM will get reward can be small or high)
Now this can be a small or a huge PVP event depending on how busy the GM is.
GM picks X teams of players (depending on the players that joins the event) and the teams have to fight against each other in one on one battle. The teams picks their first fighters and once the battle have finished the team have won a point. The player that won the battle also retreats and gives a chance to the others of his/her team. When all participants of the team have died the team gets disqualified and the winning team gets +X credits as reward for winning and stays for the next battles of the event.
The team with the most victories wins the event and gets +X credits/item
When the event ends and there is only one team standing they have won the big reward of X credits/item.