Summer says that maybe she'll put a dead frog in Seth's X-Men underoos. This is a reference to the fact that in real life Adam Brody put a dead frog in one Rachel Bilson's gift box (it was her birthday) from when they were filming "The Heights". It was from the dissecting scene, and she didn't find it until later on that day.
Summer, Seth and Anna are watching an Enrique Iglesias music video on television. While the TV cannot actually be seen, it can be heard - the video is "Addicted", featuring cast member Mischa Barton (Marissa).
Samaire Armstrong (Anna Stern) and Chris Carmack (Luke Ward) also worked together on Just My Luck (2006) as Maggie & David Pennington respectively.