Treasure World is an adventure game developed by Aspyr and published by Nintendo for the Nintendo DS handheld game console. The game is unique, as its gameplay consists mainly of collecting, making use of Wi-Fi signals picked up by the handheld.
The game utilises Wi-Fi signals from the player's surroundings to "pick up" stardust and treasures. These treasures can then be used to form musical arrangements, customise the Wish Finder, or change the environment of the game. Stardust is not only used to refill the empty tank of the ship; the Star Sweep will give players treasures in return for 20 units of stardust, and 10 when the full moon appears. This changes with the DS's internal clock.
Source: Wikipedia, "Treasure World", available under the CC-BY-SA License.