This eegg is at the very beginning of The Simpsons opening sequence of season 2 or later. Just after the clouds are parted and The Simpsons logo has faded away, there will be a distant shot of Springfield Elementary, with some shops on either side of the screen.

Look at the glass window on the left hand side of the screen. It says the words DANNY, twice. Mind you, one of the 'N's is obscured by the purple pole a bit, but as it moves along the name becomes clearer.

This is reference to Danny Elfman, the film/televsion theme composer who wrote The Simpsons opening/end theme.