The Legend of Zelda - Ocarina of Time - Codes and Secrets

Unlimited Skulltulas
You are probably one of two people, those who enjoy the hunt for the skulltulas, or those who detest it. If you are the last one, this cheat is for you ;). If you are Adult Link, you need to change to Child Link. Second, you need alot of bombs. Third, you'll need a boomerang. You'll also need to have learned the Song of Storms. Get yourself to Hyrule Castle Town. Go to Hyrule Castle and sneak in. Get in the moat and near where you first met Talon, there'll be a tree. This tree is your friend. Play the Song of Storms (you could probably use the hammer too, or bombs, all 3 should open the grotto) Before you go in, SAVE! If you screw this up, you don't want it gone forever, although there could be other grottos where this is possible. But lets not risk it ;). So, now we have saved and we're in the grotto. Equip your bombs and your boomerang, along with the Ocarina of Time. There's a skulltula in here, hidden by one of the rock walls. If you listen well, you could probably find which wall. Whatever, bomb the walls if you can't. Some of the walls have grass you can cut for extra bombs as well :D. Anyway, kill the Skulltula but do not grab the token. Now that it is dead, and it's shiny token is on the wall. Go stand as close as possible to the warp pad out of the grotto. Target it, and send the boomerang flying at the token. Now, backflip onto the platform. You might need to do this a few times to get the timing right. If done correctly, you should have one token, and the skulltula should be restored. Go back down and check. If it is there, save, if not, try again. You can do this many times, just make sure you save before attempting, but only after you've made sure its still there.

Found, tested and confirmed by Windmage

The Marathon Man
What, did you think we were going to give you a way to beat him? No! You can't beat him, you won't beat him, so let it go already!

Secrets in the Courtyard
In the Courtyard of Hyrule Castle with Zelda, use your slingshot on the window with plant inside. Some guard will get mad and throw a bomb at you. In another window, you can see pictures of Mario. Shoot inside that window and you'll get 20 rupees.

Mario Fans
Malon, the girl who gives you Epona, is a Mario fan! Her necklace has Bowser on it. Also, Talon resembles Mario and Ingo resembles Luigi.

Frozen ReDeads
Simply play the sun's song in their vicinity. They'll freeze up and their days of screaching at you are over!

Eternal Sword Glitch
This is a pretty fun glitch, getting the hang of it could be tricky though. Get close to an object you can interact with; gossip stones, people, and signs are easiest to work with. Anyway, get close to one of these, close enough to wear you can still interact with them. Crouch and perform a stab attack. This is the tricky part. In the middle of the stab, hit the button to interact with whatever it is you chose. If correctly used, your sword should look a little bit different. If you used a person, you will put your sword up, so you will only be able to tell if you pay attention while you're putting the sword up. Even if it is away, it will still be liike you are attacking with your sword. To test it out, go to a gossip stone or run into a sign. The game will look as if its kinda lagging, this is normal. Also, with the glitch activated, you cannot fall of ledges. This glitch is essential when trying to pull of the bombchu hover glitch. This glitch will be deactivated if you sustain dammage, swing your sword, leave an area, or climb up anything.

Bombchu Hover
This glitch is pretty darn difficult to pull off. First, activate the eternal sword glitch. Then, find a ledge. Z/L Target and pull out your slingshot. Pull the joystick,analog stick backwards, so you will be facing upwards. This next part is the difficult part. While aiming up, do a backflip, release slingshot, pull a bombchu and hold the R button for your sheild. If you do this correctly, you should be in the air. You are also stuck in the air unless you backflip, side step or hurt yourself. You are also stuck in Targeting mode. If you do this multiple times, you can find yourself in places you shouldn't be able to reach as a child/adult. For example, you can find yourself in the forest temple as young link. NOTE: For the glitch to work as Adult Link, I believe you have to use the hover boots.