Thanks to YouTuber Lord Zedd, an incredibly well-hidden Halo 3 Easter egg has been uncovered...after 7 YEARS. Here's how it works:
On December 25th, if a player holds down both thumbsticks, the loading screen will zoom out giving you a wider view of the Halo ring. Problem is, no one knew what purpose this actually served, well... until now.
Even if you follow these instructions, the Easter egg zips by pretty quickly - but if you slow it down (as the video does), you'll see a message hidden in the ring: "Happy Birthday, Lauren." Lauren's the name of a developer's wife, and he was trying to make everyone else's crummy $3 birthday card for their wives look like garbage.