S1E10 · The One With the Monkey

Complete story — includes the ending

The gang makes a pact not to bring dates to their New Year's Eve party, but everyone soon breaks it except Ross. While performing at Central Perk, Phoebe confronts some noisy scientists, then dates one of them, David ( Hank Azaria ), whom she brings to the party. Their relationship goes well until David and his research partner are offered a grant in Minsk, and he must choose to stay with Phoebe or go for career-making research. Monica invites "Fun" Bobby, who arrives unhappy because his grandfather just died. Joey is uncomfortable around his date Sandy's children, whom she brought to the party; she later ends up with David's friend. Rachel's plan to bring Paolo is derailed after he misses his flight from Italy; she returns from the airport disheveled and sporting a swollen lip after a fight with a woman over a cab. A desperate Chandler snaps and invites Janice before breaking up with her again after she mistakenly thinks he wants to get back together. Ross arrives with his new pet, a monkey named Marcel, who ignores Ross. In the end, everyone ends up without a date, accidentally fulfilling their original pact. When Chandler whines he has no one to kiss at midnight, Joey does the honors.