Homer scales a house and travels on rooftops after Marge asks him to keep distance from her; (Homer also hopped on random surfaces in Sex, Pies, and Idiot Scrapes.)
The couch gag is a parody of The Game of Life.
"Catatouille" is a parody to the 2007 animated movie "Ratatouille".
The title refers to Marge paying Tumi to be Lisa's pal, but it is also a reference to PayPal, which is an international e-commerce business allowing payments and money transfers to be made through the Internet.
"Booth Wilkes John" is named after John Wilkes Booth, the actor responsible for Abraham Lincoln's assasanation in 1865.
It was revealed that there is another second grade class at Springfield Elementary School, which according to Lisa, only meets up with her second grade class during tornado drills.
Marge paying Tumi to be Lisa's friend is a reference to Mean Girls.