Easter Eggs

Easter Eggs are hidden parts of a game that are mostly found by players experimenting or even by boredom.

Hey You, Pikachu.
If "Playstation" is spoken in the mic, the pickachu will become angry, representing Sony's and Nintendo's rivalries.

Diamond/Pearl
After a player defeats the Elite Four, if the player talks to Dawn or Lucas (Depending on their gender) on thier birthday, they will wish you a happy birthday.