-After completing the"The Pillar Of Autumn" mission, wait for the credits to end to notice the loading object turn into a different shape. Most people will not notice it, but it is a "7". This is a reference to Bungie's favorite number.
-The highest existing rank is "Legend" but Bungie added 7 additional ranks, which are Mythic, Noble, Eclipse, Nova, Forerunner, Reclaimer and Inheritor--yet another reference to Bungie's favorite number.
-Play through the "Winter Contingency" mission. When you reach the part where Noble 2 or Kat is trying to shut the door, go inside and go through the hallway until you find the dead person on the floor. Kat will tell you to "Check his dead body", or something similar. Allow the cinematic to play. When Kat kicks the assault rifle over to you and your character picks it up, look on the assault rifle's ammo. It has Bungie's favorite number on it.