In "The Excelsior Acquisition", Stuart, thanks to his uncle who happens to be Stan Lee's dermatologist, manages to convince Stan to come over for a comic book signing. Sheldon, Leonard, Howard and Raj are all excited to meet him, but Sheldon has to forfeit the opportunity due to a court appearance regarding a driving violation whilst carrying Penny to the hospital (in "The Adhesive Duck Deficiency", although unseen, he drove past a red light). The guys tease Sheldon about how everyone not only got to meet Stan Lee, but also went out with him for gelato and became first-name acquaintances with him (with the exception of Raj, who, it seems, bugged Stan by complaining to him about the number of superheroes with alliterating names he has created).
Sheldon is visibly displeased with this turn of events, and Penny feels guilty since it was her fault in the first place that Sheldon received the fine and the summons. In an attempt to remedy the situation, Penny takes Sheldon to Stan Lee's house so that the two could finally meet. Stan is outraged about how Penny and Sheldon have the nerve to come to his house uninvited, but when he retorts sarcastically to Sheldon to watch the Lakers game, Sheldon takes it as a genuine invitation and enters Stan's house. Stan has no other choice but to file a restraining order against Sheldon, who proudly hangs it next to the restraining order from Leonard Nimoy.
Stan Lee passed away on November 12, 2018.