Note: This could and will never happen. This is just for fun.
Imagine that you find a secret door on some level that leads you to a small explorable area full of giant mushrooms. As soon as you start getting the idea that this might be some sort of a Minecraft reference, a Creeper comes out of nowhere and just blows you up. lol…
> I like it!!! Anything with a Minecraft reference gets a thumbs up …sssssssssssss
coughcough at this.
Anyways, I think a really good easter egg would be a secret gate that allows you to go back to Halo 2 with the same graphics and everything. You would to activate a certain number of skulls in a pattern to activate this secret gate. Other than that, put a flaming recon like from Halo 3 in one of the missions and let the AI have the voice of Stosh.