Throughout the fourth season, it becomes obvious that Penny is still in love with Leonard. It is unclear whether or not Leonard has noticed this, though he clearly is still interested in Penny. In "The Benefactor Factor", an older rich woman (Jessica Walter) propositions Leonard in exchange for a large donation to the physics department; he initially resists and she admits that she planned to make the donation anyway, after which they engage in a one-night stand. Leonard arrives home the next morning, whereupon Penny recognizes his "walk of shame" and Sheldon thinks Leonard has a future in becoming a gigolo to rich ladies in exchange for donations.