Near the beginning Steve mentions that his Parthenon is due tomorrow, but at least one more day passes before we see them building it.
Steve says he's building a Sugar Cube Parthenon, but when we see it it is made of Q-tips.
Dick suggests that Christopher Lloyd could have played the Colonel Mustard character in Clue. However, Christopher Lloyd was already cast in that film as Professor Plum, and so would not have been available.