 In the episode "Homer3" (TreeHouse of Horror) where Homer enters the  third dimension at the back of the bookcase, you can see the numbers  and letters 46 72 69 6E 6B 20 72 75 6C 65 73 21 float by. This is  actually hexidecimal code for "Frink rules!" (you can check by  putting this code in your browser bar (only works in IE):  about:%46%72%69%6E%6B%20%72%75%6C%65%73%21).