This was the 100th episode, thus the references to "100" in the show.
The list of the Death Pool they find in Kevin Iverson's house, contains many names of real life celebrities, as well as made up celebrities. There are 9 columns. In the 6th column (counting from top left going right, the column that is in the middle, to the right) there are a couple of names, that is crossed out, indicating that the person had died. The first name, that is crossed out, is Aaron Spelling (creator of Beverly Hills 90210 and father of Tori Spelling, who plays one of the main characters in the series), who had died a couple of month before the episode was first aired.