I got a few arduino boards too....
Tested a small program to run motors and for sensors to pick up objects - quite interesting, and easy too.
I have not done much, but I have played with them abit.
These things are quite robust -
and one small board like the "arduino duemilanove" or the great
"atmega" - can do quite a lot - not discounting:
>digital
>analogue
>serial
>parallel
Input and output.
Such boards are the things that create those car-tracking devices and car-alarms, not forgetting the door and window sensors.
Its practically a computer in itself that you can use to run things remotely. Guys should really look at this.
w/regards
SNN