Easter eggs aren't always made of chocolate and in my opinion, the best are those found as hidden bonuses in games, DVDs and music.
There are thousands of Easter eggs available on hundreds of games and add a little something extra. Some are interesting artwork (GTA) while others are hidden characters (Mortal Kombat) and game options (COD: Black Ops).
In some renditions of the original game, if you see a shadowy figure fly across the moon on The Pit stage then beat your opponent untouched and without blocking, you'll get the chance to fight Reptile. If you win, you earn a cool 10,000,000 points. If you lose, you've wasted a rare opportunity.
Grand Theft Auto IV
If you fly a helicopter to the Statue of Liberty and jump down to the highest platform with four doors on it, walk through the door with blood stains and the sign 'No hidden content through here'. Climb the ladder and you'll find the beating heart of the city (and if you shoot it, it bleeds).
Call Of Duty: Black Ops
From the main menu when you are held captive in the chair, look around. To break free of your bonds press the left and right triggers in quick succession. This will release Mason as he struggles and earn you an achievement/trophy. Furthermore, move to the computer and if you type DOA or ZORK into the terminal you'll unlock playable mini games and another achievement/trophy.
Hardly a game but if you open this popular bit torrent program, select About in the Help menu and press T you'll be able to play Tetris.
There are heaps of little treasures scattered in games and www.eeggs.com has many listed. Have you come across any? What's your favourite, be it found or heard of?