Just giving a plug for this free event. For those who want to give other microcontrollers a try, this seems like a good primer on ARM Cortex mcu's. I like ST's selection of form factors and cheap dev boards, and the mbed development environment is pretty easy to use if you're coming from Arduino. You get lower power consumption, better performance, more I/O, and good library support for peripherals. Very maker friendly for building a couple prototypes.
The seminar is on a work day though.
Eric Tsai