15. Other than Ross and Rachel (who met, of course, as kids with Ross being Monica's big brother and Rachel being her best friend), the main couple of "Friends" was Monica and Chandler. Friends first and married later, when did they originally meet?
From Quiz "Friends" - How Did They Meet?
Answer:
When Ross, Chandler's college roommate, brought him home for Thanksgiving
When the series began, Chandler and Monica were both already living in their respective apartments across the hall from each other, but we later learned that they knew each other before living in the building. Chandler and Ross were roommates in college, and we found out in the season five episode "TOW All the Thanksgivings" that Ross brought Chandler to his parents' house for Thanksgiving 1987 and that's when Chandler and Monica first met. In the same episode, we found out that Chandler calling her fat behind her back that day was what led Monica to lose a lot of weight.
Chandler and Monica first slept together in London at the end of season four, began dating in season five (secretly, at first) and married in the final episode of season seven.