The king summons several adventures for a mission (say 50) after a short question and answer session you are asked to enter the door to your right. And there is the party. Pick which characters are in the room in which order and give them some time to talk to each other. Then the king comes in a briefs them on their mission.
I have used this so I could have characters that were moderately experienced but had not worked together. I hate it when I'm at a con and the GM says you are a party of adventures that have adventured together for x number of years. Then you all fight among your selves or do not act as a group.