An adventuring group meeting in a tavern is traditional in fantasy role playing games. The clich� has traveled into other genres, too. I've used it in space opera settings, Call of Cthulhu adventures, pulp adventure settings, and more.
Eventually, though, your players get tired of it. It's hard for each campaign to catch and hold their interest when it starts out like a repeat of the last one, and the one before that.
There comes a time when you have to try something different.
Start From Humble Beginnings
Typical adventurers are expected to have already struck out into the world on their own, and to have learned the basis of whatever profession they have chosen. They're not especially capable, but they do know the basics.
By getting rid of that assumption, we can roll the clock back and see what happened to the characters to cause them to leave their homes and families and take up the adventure.
I used this effectively in one campaign where each player played some solo adventures showing how their character decided to take up their profession. The paladin and the fighter of the group were twin brothers working for their blacksmith father. We saw how they viewed, as teens, the events that would later lead them into the campaign. They joined the city guard to contribute to the defense of the city, and there received their training.
We went through the same sort of thing with all the characters. By the time they met and banded together for the campaign, they each had a rich history and a shared knowledge of the game world. They had reasons for what they were doing.
This sort of thing can be overdone...players won't want to do this for every campaign, and especially not for adventures that are only going to last a few sessions anyway.
But now and then, it can add a lot to a new campaign.
Assume Experienced Characters
Another thing that works well for some campaigns is to start characters off more experienced than traditional starting characters.
These are not characters who are just starting out in the world, looking to find their way. These are characters who already have a history, enemies, and friends. They may hold positions of power and/or infamy in the land.
The key to doing this well is to do some single character sessions where each player gets to see just why their character is getting involved in the campaign. By the time all the characters come together, even if it's in a tavern, they all have their own unique motivations for getting involved.
Some may want to defeat the menace, others may want to betray the group. These motivations, whatever they are for each character, add richness to the campaign.
Do The Unexpected
My all-time favorite opening to an adventure, that I haven't been able to use yet, is having all the characters gathered together in one place, perhaps a tavern. The point at which they know something is going to be different about this night is when a duplicate of one of them appears, apparently traveling from a future time.
This duplicate manages to gasp out a cryptic warning before dying of hideous burns. The character whose duplicate just died would certainly have an interesting adventure ahead of her!
Regardless of how you normally open adventures, remember to mix it up and do something different now and then. Your players will like the variety, as long as you also give them a terrific campaign.