Munchkin Easter Eggs is a 15-card booster that contains Munchkin cards with an Easter theme. The seven Treasures and eight Doors included have the standard Munchkin card backs, but the card fronts use a different color scheme: the Treasures have a green border and a yellowish background, while the Doors have a light blue border with a red and white background. (There's some sort of pattern/image to the background.)
The cards do not add any new or unusual mechanisms or interactions, but they bring a good bit of humor to the game. For instance, who wouldn't be afraid of a (Chocolate) Little Bunny 'Thulhu?