What are the Minecraft Easter eggs?

I was looking at this answer and I didn't realize that Minecraft had some Easter eggs in it. Besides the Christmas chest Easter egg, and the sheep Easter egg, what else is there?

Solution 1:

• Halloween - on October 31st, some mobs will have pumpkins on their heads, and may drop a pumpkin if killed.

• Christmas - between 24th - 26th December, chests are reskinned to look like presents

  

• Mobs - naming a sheep or a sheep spawn egg 'jeb_' will result in rainbow sheep (a sheep which cycles through the colours)

  

• Mobs - naming any mob/mob spawn egg 'Dinnerbone' or 'Grumm' will make it render upside-down

  

• April Fools - Mojang often have special jokes for 1st April, e.g Minecraft 2.0 from Apr 2013

• Text for the updates/bugfix lists often includes 'Removed Herobrine' as a reference to an urban legend about the game

  

• If you ever kill Notch himself, he drops an apple

• Crash logs occassionally include tongue-in-cheek statements such as 'Don't do that again'

• On the game's main menu, there is a 0.01% chance that it will say Minceraft instead of Minecraft

• If the file with the list of splash text lines (the yellow text on the main menu) is deleted, it will display as 'missingno' which is a reference to the infamous glitch in the early Pokémon games.

Sources - many, many hours of Minecraft (and this wiki page)

Solution 2:

Also Deadmau5 has his trademark ears in game. They are visible to everyone and in the vinilla client.