This 3D printed Jeep by Nicolas Roux, features tank tracks, and is controlled by an Arduino via an Android app over Bluetooth.
The Arduino itself isn't really capable of playing music on its own, but add an Anniken Andee shield, and you're good to go!
Kerimil shows us how to communicate between Arduino and a custom Android app. It uses Bluetooth, and the MIT App Inventor for the app code.
The new Raspberry Pi 3 B+ offers a faster processor, dual-band WiFi, Gigabit ethernet and Bluetooth 4.2 for the same price as the base model 3.
The LightBlue Blue+ is a great little board, sporting Bluetooth, a battery, an accelerometer and a temperature sensor.
The BLEduino is a tiny Arduino-Compatible development board with Bluetooth 4.0, built in. Control anything from your phone!