I just ran my first two sessions as GM and we are probably going to be adding a 4th player to the group soon (making 5 of us total). I'm trying to thing of a good premise for the party to meet the new character and be joined by them and not just have the new character appear into their midst all of a sudden as if they were there the whole time. I'm going to let the new player make their back-story and then try to find a good way for them to get mixed in to the adventure. The stereotypical situation where the party finds the new player being attacked by goblins and the new player pledges to join them after being rescued would work, but I'm looking for something a bit more than that.
Are there any good guidelines/examples for adding a new player to the party story-wise? How can I make the meeting of the new character and the party a momentous occasion instead of just a "Hey, wanna join us?" situation? What good twists can the addition of the new character provide to help in this respect?
NOTE: Examples are wonderful and highly welcome, but please also mention the process of creating the storyline so this is more than just an "accumulate a list" question. :D