MBED is a low cost, low barrier to entry ARM based microcontroller development platform. No software, no dongles, no licenses, no ICE. All you need is a USB cable and an internet browser. The C++ development environment is hosted online. To test your firmware you drag and drop the .bin file onto the MBED device and it's installed and ready to go.
In this video I've used MBED to give my Big Mouth Billy Bass (BMBB) a brain transplant. He used to sing and dance along to Bobby McFerrin ("Don't worry be happy") and a cover of the Talking Heads ("Take me to the river"). Pretty entertaining, but what if you could download new audio clips and new movements? What if BMBB could get his new songs and choreography from a microSD card?
MBED provides C++ libraries to interface to all of the microcontroller features (A/D, D/A, timers, digital I/O, PWM, etc.) and made it a snap to write a .wav file player to play the sound and use the PWM outputs to control the motion.