Kristen Bell was originally attached to play Sasha and was forced to drop out after she became pregnant. She was slated to be replaced by Evan Rachel Wood until she became pregnant and dropped out of the role as well.
Leighton Meester and Adam Brody are married in real life.
In early drafts of the script the story began with Paige making a drunken promise to Sasha not to get married until same-sex marriage was legal. After same-sex marriage became legal in California this plot line was abandoned.
In the scene where Tim crashes the girls' TV night and is shouting lines from The Big Lebowski, he is drinking a White Russian. This is the signature drink of Lebowski's protagonist, "The Dude."
Monte Markham plays Adam Brody's father Ken, however it appears that this is only implied as he was given only a few seconds of screen time in one scene, no dialogue and was not formally introduced by name. Markham also played Blanche Devereux's gay brother on "The Golden Girls", which may partially explain his cameo in this film given its LGBT story.