S9E6: The One with the Male Nanny

Ross and Rachel hire a nanny for Emma named Sandy and things seem to be going great. However, Ross is uncomfortable having a male nanny. Meanwhile, Chandler becomes upset when Monica says that somebody from her new job is the funniest guy she's ever met. Also, after Phoebe and Mike decide to take their relationship to a new level and exchange apartment keys, Phoebe gets a surprise visit from her ex-boyfriend David.