David Wozniak (Vaughn) is a hapless deliveryman for his family's butcher shop, whose girlfriend Emma (Smulders), an NYPD officer, is pregnant with his child. One day, David returns from work to find a lawyer representing a sperm bank where he gave donations during his student years, who tells him that he has fathered 533 children through his samples, and that of those, 142 have joined a class action lawsuit to force the fertility clinic to reveal the identity of "Starbuck", the alias he had used.
David's friend and lawyer Brett (Pratt) represents him as he tries to keep the records sealed, but David starts to have second thoughts about it.
This film contains examples of:
- Amoral Attorney: Brett sees the lawsuit as a breakthrough in his mediocre lawyer career and encourages David to go for it even though David is getting on good terms with his 142 kids.
- Cool Old Guy: David's father, whose humble origins as a Polish immigrant made him a struggling and caregiving person to his family and customers. At the end of the film, he gives David all the earnings from his delivery job to pay the debt with the Russian mafia.
- Glorified Sperm Donor: David sold a great amount of sperm to the sperm bank, fathering over 500 people under a pseudonym. Once most of them grew up, they tried to nullify his anonymity through legal means. David sued the sperm bank to prevent this from happening, and won the case. Not long after, he decides to reveal his identity publicly. All his children began to love him dearly.
- Leno Device: At one point we see a Jay Leno monologue where he jokes about David's predicament.
- Massive Numbered Siblings: Although technically half-siblings, David has fathered 533 children with various mothers due to his sperm donations. Many of which have come together in a lawsuit to try to uncover David's identity.
- Mood Whiplash: Several of them as the film zigzags between comedy and drama. The film goes to hilarious scenes like David pretending to be a Mexican and Brett's children sleeping in the sandbox to a teenager almost dying of overdose, David meeting his disabled son and the Russian mafia performing a drowning torture on David.
- One-Hour Work Week: Subverted. It is mentioned repeatedly that David's misadventures throughout the movie are occurring while he is supposed to be delivering meat.
- Parking Problems: As a delivery person for his family's butcher shop, David has his delivery truck repeatedly ticketed for parking improperly. He uses the truck to pick up the shop's basketball team uniforms to wear during a team photo, which his family doubts he can retrieve and deliver in time for the photo due to his unreliability. David manages to retrieve the jerseys, but the truck is towed with the jerseys inside.
- Trespassing to Talk: How the Amoral Attorney chooses to inform David of the lawsuit filed against him.
- "Well Done, Son" Guy: Brett's mother has always mocked him for not doing anything worth in his life and career, and sees the Starbuck case prove her wrong.