Since this was the first episode ever filmed, the cast and crew didn't know exactly how to work out costume changes yet. They originally wanted to run through the episode like a play, with no long breaks. So, this is why Lucy wears layers of clothes throughout the episode. After this episode was filmed, everyone agreed that this "no breaks" method wasn't going to work, but they still were afraid of the 300-person audience getting bored while the actors changed costumes and got sets ready for the next scene. This problem was solved by having Desi's orchestra play for the audience during intermission times.
Lucy mistakes her jar of cheese dip for the jar of cold cream while intensely reading. She dips her cracker in the cold cream and gets a nasty-tasting surprise. The reaction from this gag was the first laugh ever recorded on the show.
During the scene with the switching of the glasses, if you watch closely, Ricky actually ends up with the glass containing the sleeping pill.
When Lucy and Ethel confront Ricky at the club, Lucy yawns due to the sleeping pill she's been slipped and Ethel yawns right after her. Ethel's yawn was unscripted and Vivian Vance was simply responding to seeing Lucy yawn.
Most early television show bedroom scenes have beds separated, this show has beds pushed together.