(1) Tyler blackmails the head of the projectionists union, saying that he has to pay him or he'll tell everyone about the porno slides in the children's movies.
(2) Our narrator blackmails the head of the Pressman Hotel, saying that he has to pay him or everyone will know that the Pressman Hotel is "where the richest people in the world ate pee" (15.30).
The projectionist beats the snot out of Tyler while he laughs it off.
The head of the hotel doesn't buy it, though. So our narrator beats himself up and blames it on the hotel manager. After all, who would believe someone would beat themselves up?
With their blackmail money, Tyler and our narrator are now able to have fight club every night of the week. Sunday, Monday, fight club days. Tuesday, Wednesday, fight club days. Thursday, Friday, fight club days. Saturday. Fight club day. Fighting all week with you!