When Christopher Walken and Rachel McAdams are dancing at the engagement party, Walken kept saying "fart" to keep McAdams smiling after dancing had become quite repetitive.
The painting given to Jeremy (Vince Vaughn) by Todd (Keir O'Donnell) was kept by Vaughn after filming.
Rachel McAdams got her certification in sailing to prepare for her role. She says she can now handle a 26--foot boat.
Rachel McAdams listened repeatedly to Fleetwood Mac's 1975 song "Landslide" to prepare for emotional scenes. Owen Wilson said the song made her cry immediately: "It was like turning on a faucet."