The One In Massapequa - S8-E18
Corrected entry: In 'The One In Massapequa,' Ross and Rachel have to pretend to be married for the night at the party. Unless everyone was blind, then wouldn't someone notice Rachel and Ross didn't have a ring on their finger? (00:06:30)
Correction: Not every married couple wear wedding rings. Ross mentions that Rachel said something about a dove placing the ring on her finger, but remember, Rachel is pregnant during this, it is very possible that people thought she'd just taken off her ring because her hands had swollen due to the pregnancy.
Kara