In episode " The Conference Valuation " (S12E17), the story splits between a high-stakes pharmaceutical convention in San Diego and a chaotic "science day" back in Pasadena. The Pharmaceutical Convention
Danny offers Penny a job, leading her to realize she doesn't always feel appreciated by Bernadette. [S12E17] The Conference Valuation
Back at home, Howard is left alone with the kids and invites the guys over for company. The day takes a turn when Sheldon finds a book on developmental experiments for children. In episode " The Conference Valuation " (S12E17),
Penny and Bernadette travel to San Diego to promote a new drug. Penny, thriving in her role as a sales lead, catches the attention of Danny, a representative from a rival company that Bernadette despises. The day takes a turn when Sheldon finds
Leonard realizes his mother, Beverly, performed similar experiments on him throughout his childhood. When he calls her to complain, she reveals that the "experiment" on him never actually ended.
Sheldon and Amy use the children to test cognitive and motor skills, much to Howard's amusement and Leonard's distress.
Watch Penny's masterful drug-pushing pitch at the convention: