When Schmidt hurls the broom, it accidentally sticks in the wall and reveals the fake bricks of the set.
For Halloween, Jess dresses up as Joey Ramone-a Quimby. Coincidentally, the actress who played Ramona Quimby in Ramona and Beezus (2010), Joey King, guest-starred back in season 1 episode 14. So Jess' Halloween costume combines King's first name and the character's name that she plays in the movie, even though Jess is actually referencing musician Joey Ramone.