When Donna angrily enters the basement looking for Eric, she enters through the door. Moments later, when she leaves, Fez has to unlock the door's deadbolt to allow the door to open.
When Hyde catches Red sneaking a burger and fries, Red is blackmailed into handing over his fries to Hyde. In that moment, the signature In-N-Out Burger red palm trees logo can be seen on the fry boat. Although In-N-Out opened in 1948, the company had yet to move that far east.