Vintage Promo:
Go to the main menu on disc 1 and highlight "photo gallery", press left on your dvd remote to highlight the "Hercules" logo, press enter and you will be treated to one of the original promos used to promote the series.

Vintage Promo:
Another promo is hidden on disc 8 in the same place as the first egg (the hercules logo in the upper left corner of the main menu.