I've been playing around with the Arduino platform for a while and it's really great fun. There is just no hassle with hard programming language or the need to fully understand whats going on inside the chip.
Even though I prefer using real PIC Microchips in C or Assembly I still think the Arduino is a good tool to let your creativity unfold.
Take a look at this video to get an idea about what it is or go to http://www.arduino.cc
The Arduino is so good that even Dave Jones thinks it's fun