The Legend of Zelda: Majora's Mask/Don't Fall Asleep!

Requirements

 * Giant's Wallet with 500 Rupees
 * Completed Event: DA BOOM

Rewards

 * All Night Mask
 * 2 Pieces of Hearts

What To Do
Begin by completing the Seaside Skulltula House. The reward is the Giant's Wallet, which allows you to carry 500 Rupees. Now complete the event DA BOOM.

Curiosity Shop Man
On Day 3 the Curiosity Shop Man will be selling the All-Night Mask. Purchase it for 500 Rupees and warp back to Day 1.

Anju's Grandmother
On Days 1 and 2, enter the Stock Pot Inn and speak with the old lady in the back while wearing the All-Night Mask. Listen to her stories of the Carnival of Time (Consumes Two Hours) and the Four Giants (Consumes One Day). After the Carnival of Time's story is over, she'll ask you a question. Answer correctly to win a Piece of Heart. The Four Giant's question is tricky, because it's really a trick question! Answer honestly to win another Piece of Heart.