There is no better way to learn electronics than building and experimenting with your own gadgets. Arduino is a wonderful platform for doing just that. CulBox is an open source wrist watch for Arduino with Bluetooth. It has a 32 bit Arm Cortex processor, 6-axis sensor, microphone, 3 push buttons, and a 1.5″ OLED display.
The device comes with a multi purpose app to use as a template for your own app in Arduino. It supports microSD cards.