Cairo Station Vacation
The colloquially-termed Cairo Station Vacation is a small programming oversight in the level Cairo Station of Halo 2 campaign that allows one to explore parts of the level previously thought to be inaccessible, or simply just scenery.
How To Get There
First play through Cairo Station until you reach the area with the two Ranger Elites waiting just outside the door to the outside of the station. Kill the two Elites, and any other ones who may or may not be present depending on level of difficulty. Then find the geometric half-arch that leads onto the top of the station. Just jump up onto it and then the top of the station. Then walk over to the area closest to In Amber Clad, and jump onto In Amber Clad. Note: The two bridges that lead to the side of the Frigate cannot be used to get on top of her, because halfway across there are invisible walls blocking your path. Go past them and you will be able to jump on top of her from a point near the ship.
What To Do
All sorts of fun can be had here. You can walk around the entire length of Cairo Station, see the other MAC bay, explore the other ship port, or explore In Amber Clad herself - you can even get inside her engines with a little patience and good jumping and timing. Another fun thing is to go to the orange glass on top of the station, and sink in. On two of these orange glass panels, you will see areas of the station you were in earlier in the mission, one of them being right outside the bridge. One of them requires you to crouch in order to see inside. You can also jump for a dive and not die if you just had the Blind Skull. Once there, you can see the room that Sgt. Johnson and Miranda were in.
Also, you can skip the part where you have to take the elevator and fight three more Elite Rangers. However, the three rangers will not appear nor will the door to the bomb spawn. You can also see one of the Covenant boarding craft that is attached to the station. However, if you try to jump on top of it, you will simply fall right through it and die.
Note: while in the glitched area, you will seem to move slightly slower than normal, and your shadow appears to be a little slow when you switch weapons.