The Rocky Horror Picture Show
In The Rocky Horror Picture Show, a popular 1980s musical film, there are actual Easter eggs hidden within certain scenes. The rumor is that the cast and crew had an actual Easter egg hunt on set and couldn’t find them all. This one made it into the film, and only the most dedicated fans have known the story behind it.
Raiders of the Lost Ark
Hieroglyphics of C-3PO and R2-D2 are snuck into the background of the scene on one of the columns. It's funny because the story was written by Star Wars creator George Lucas, and any time he works on an unrelated film, he tries to sneak in something from his own intergalactic universe.