I have a couple. First, wearing the Fierce Diety mask all around everywhere. This one is tricky. You need to go to that place where you help the kid get the sun mask (it is blocked all except on the third day I think). You go there on the first day or second day, depending on how much time you want. It is closed right? Well, run at the crack on the right side of the wall (I think it is right but I don't remember) and roll into it. It will probably take a few tries but you can slip right through and start in the whole deal with the kid and the mask on the conveyer belt. If you equip the Fierce Diety mask, Link will put it on right after the mask goes through the first hatch. Complete the little part, and you can now walk around wearing the FDM!!! Very cool.