How Two Characters Met

How two characters (PCs and/or NPCs) met or know each other [fantasy] [adventurers]

When you were young you travelled together and got into an argument
You have heard the other mentioned often by a mentor or friend
A few weeks ago you met in a temple and met some strange characters
One eventful evening you got into trouble together and decided to form an adventuring group one day
You grew up together as best friends in a mountain farm
When you were young you met somewhere you shouldn't have been and got several people drunk
A few years ago you were prisoners together and were part of a tight-knit group
A few months ago you met on a ship and had a argument about politics
One memorable night you had a argument about sport and had the best night of your lives
You have a mutual friend who introduced you both at an annual festival