The Boyfriend Complexity - S4-E9
Corrected entry: Penny's father says, "I want grand kids before I die, and I want them to grow up in a house without wheels," but in season 2, E20, Penny asks Leonard to buy a comic book for her 13 year old nephew. Her nephew would be her father's grandson.
Correction: Her mother may have had a child with another man before marrying her father, which would make the nephew a step-grandson and not a "real" one in her father's eyes.
Captain Defenestrator