9x23/24 "The One in Barbados"

The gang goes to Barbados for Ross's conference. David (Hank Azaria), Phoebe's Scientist Guy, almost proposes to her – but her ex-boyfriend Mike does so before he gets the chance. Ross and Charlie find they have a lot in common. Rachel and Joey get even closer. Monica's hair reacts to the humidity. Joey and Charlie break up when he realizes they have nothing in common. He later sees Charlie and Ross kissing, and so he kisses Rachel. Monica and Mike play ping-pong to the distaste of Chandler and Phoebe.