Izzie is wearing the sweater she knitted for Denny in season two.
First episode Eric Dane is credited as part of the main cast.
When Karev and O'Malley are talking about superheroes, they mention Batman and Robin. Chris O'Donnell, who guest stars as Dr. Finn Dandridge, played Robin in Batman Forever (1995) and Batman & Robin (1997).
Katherine Heigl talks about her dislike of weddings and bridesmaids. She later plays a super bridesmaid in 27 Dresses (2008).
Every episode of the show is named after a famous song. "Sometimes a Fantasy" is a song by Billy Joel.