You lazy ingrate!
Read up then!
http://bulbapedia.bulbagarden.net/wiki/Pok%C3%A9mon_Mystery_Dungeon:_Explorers_of_Sky
"The Sky Jukebox is also a feature. Players can play every song used in the game.
Spinda's Café: One can recycle excess items for better items, new dungeons, or specials (such as iron, zinc, protein). Big prizes can be won from the lottery. The café also has a Juice bar. Feed your food items (mainly power-ups and gummies). The bonus to this is unlocking new areas, receiving eggs, or recruits.
Job requests and secret rank missions are also here (as well as having the bulletin in the guild).
While exploring dungeons, you can occasion step on some hidden stairs. They can lead you to the Secret Bazaar. Or the stairs can lead to treasure rooms.
A new location, Shaymin Village, is unlocked after completion of the main game, featuring a tribe of Shaymin, where the player also allies with Team Frontier to reclaim the trail leading to the top of the nearby Sky Peak mountain. An accompanying Shaymin demonstrates its ability to instantly purify polluted environments, its use of the Gracidea flower to transform into its Sky Forme, and can be later recruited into the player's party.
Players only lose half of their money when defeated in a dungeon, instead of all of it.
Raikou, Entei, and Suicune are no longer acquired with the Mystery Part and Secret Slab or in Final Maze, and are now in three new dungeons called Southeastern Islands, Inferno Cave, and Treacherous Waters. These dungeons are unlocked through random challenges in Spinda's Cafe. However, these challenges cannot be taken until the player's team has reached the Master Rank.
On the beach, bottles can wash up and they contain requests or sometimes a "treasure memo," meaning, it can lead you to big treasure."