When Nick is talking to Kate for the first time, it is mentioned that he doesn't have a Facebook account. Nick states that he is "off the grid". In fact, Jesse Eisenberg, who plays Nick, also played Mark Zuckerberg, the founder of Facebook in 2010 film The Social Network (2010).
The character of Dwayne is obviously a big fan of 1980's thrash metal. The shirt he wears for the majority of the film is the album cover from Metallica's "Master of Puppets" (1986). Additionally, Dwayne's ringtone is "Raining Blood" by Slayer from their album "Reign in Blood" (1986).
Fred Ward is credited as The Major, but near final third of the film when he is walking through his house, his oversized lottery check is shown on the wall, issued to him. Therefore, his character's name is Jerry Mikowiski.