Heres a few more festival related tips:
Try and use video isolators when using video input cards in festival situations (a client destroyed 10x PE4 cards last year before installing a £100 isolator on each input)
Try and keep your server in the shade (and dry) - as they get hot in the sun and don't work well in the wet... Ensure they have good ventilation (and are not next to a hazer)
Also watch out for loose PCI cards and sub base... as it can cause the Mac to crash on the 1st cue... A Shock-mounted rack can help here to avoid vibration. Some foamed racks have been affected by this too.
UPS are a good idea too - especially on generator power when the LD flashes all his Molefays and the voltage drops by 20v - then goes over-voltage by 20v afterwards...
Keep a backup of your content and show file on an external HD with you (seperate from the server) - so when your server is delivered to the wrong festival site (or left in someone else's warehouse), you can borrow one from a colleague working with another band...
S