At the end, right after Jackie apologizes for lying about making the brownies, the plate of brownies goes from Jackie's arms to Christine's arms and right back to Jackie's.
When Jackie said that she made the coffee, the cup is empty.
Jackie says that she would have used Donna's curling iron, but it smelled like potatoes; Donna shrugs and says that her dad used it to make curly fries. Curly fries didn't come on the market until 1985, in Washington, or more widely when Arby's introduced their Curly Fries in 1988.