This is at least one way to do something cool on every map in halo 3. The more the merrier, and having an experienced 'Hot Dropper' (I'll explain that later) with you will really help. Most of these need 2 people and A LOT OF COMMINICATION! So have fun, don't get shot, and eventually, you might want to consider getting a life.
EDIT: this was made a loooong time ago, so anything that says I will change, I wont, I have a life, sorry everyone, but make do with what I posted
Step 1: Crouch Jumping
Not much too It, simply just crouch while you are in mid air.
Step 2: "Hot Dropping"
Thats what I call it. This requires 2 people. first you spawn a 2 way teleporter. Then you have another person hold a teleporter in place outside the map. Go through the first teleporter in monitor mode. Obviously sometimes you explode, but if its unblocked it is perfect to get out of map (reffered to as out-map (respectivly In-map))
Step 3: N00b Spawning
Simply delete all the spawn points then place one where you want to go. (this is only used once or twice in the tutorial.
Step 4: Turret Switching
This one is fairly complex. Spawn a turret with the back against the object you are going into. Jump on top of this turret, crouch, and get in it. Pull the Right TS all the way back and press up on the dpad. This is another great way to get to places hot dropping can't get you to
Step 5: "Double Jumping"
Have one guy stand in a spot. Have a second jump on top of him. when the guy on top jumps, the guy on bottom jumps shortly after. Then have the guy on top rapidly pressing a and he will jump on top of the bottom guy (who is already in the air) this is an equivelent to grenade jumping.