During the scene by Kirk's parents pool, Kirk is begging his brother not to embarrass him. Dylan turns to put his back against the side of the pool and his left elbow knocks over a beer can. In the next shot, behind Dylan, he is between two upright beer cans.
Prior to their first date, Molly, her sister, and Patty are shopping. The sister holds up a dress, and the consensus is that it is horrible. When Molly and Kirk go to visit his family, Marnie is wearing that very same dress.