I Love Lucy - Wrong Glass
This slip-up is in the episode where Lucy thinks Ricky is trying to kill her. Watch the scene where Ricky puts a "mickey" in Lucy's glass. Pay attention to the glasses. After she switches the glasses when Ricky isn't looking, then he switches them back when she isn't looking, she winds up drinking the glass that she left for Ricky.
on 03-16-2001 and