what is arduino?
arduino is an open-source electronics platform based on easy-to-use hardware and software. it's intended for anyone making interactive projects.
arduino boards are able to read inputs - light on a sensor, a finger on a button, or a twitter message - and turn it into an output - activating a motor, turning on an led, publishing something online. you can tell your board what to do by sending a set of instructions to the microcontroller on the board. to do so you use the arduino programming language (based on wiring), and the arduino software (ide), based on processing.