wow, just look at all those optoisolaters on that board 
Seriously, a good old fashioned diode simply no longer good enough to protect your arduino from voltage spikes??! - and if anyone think's it's not good enough, I once managed to Restart my Arduino board from messing with a relay (switching it on and off, with it's terminals connected to the board, purely accidentally, but nothing broke, Atmel did a splendid job with their atmega chips 