7. Schwarzenegger's King Lear - The Lost World: Jurassic Park
A really obscure easter egg that will only be understood by those with a wider awareness of Spielberg's more obscure works comes when the characters enter a movie theatre. To the left of the screen stands a huge advertisement for William Shakespeare's King Lear, starring none other than Arnold Schwarzenegger. The reference is obtuse even by easter egg standards given that it references a lyric from the Spielberg-produced cartoon Animaniacs, which sang, "But 'Paramount hurts and they're losing their shirts' means Schwarzenegger's doing King Lear." If this is an easter egg you spotted yourself you should probably consider yourself an easter egg hunting professional.