Well meaning Willow: Xander's wariness of Willow's spell casting is well founded: he had been on the wrong end of a love spell before, thanks to Amy's magical trickery in Bewitched, Bothered and Bewildered.
People of Sunnydale: According to the 'Welcome to Sunnydale' sign that Spike knocks over at the beginning of this episode, Sunnydale's population is 38,500 (and, no doubt, getting smaller all the time…)
Singing Simpsons: Willow's lament that her test scores make her "Cletus, the Slack-Jawed Yokel" refers to a simpleton character in 'The Simpsons', who first appeared in the 1994 episode "Bart Gets an Elephant". Cletus is married to his sister, Brandine. They have 26 children and a "smellhound" called Geech. Cletus even got his own theme song in the episode '22 Short Films About Springfield': "Some folks'll never eat a skunk / but then some folks'll / like Cletus the Slack-Jawed Yokel"!