If you're going on Wednesday evening to uncrate, be sure you put one or two charged cordless drills with driver bits in an easily accessible place in your checked suitcase.
Also, if you have any super critical tools that you have to use a lot, see if you can get a pocket-sized version and keep it with you. (i.e. I always have a hex wrench for our encoder spring couplers and arm pot spring coupler on me, as well as a tether, programming cable, and auto/disable switch (thanks Pascack PiOneers) in my laptop case.)
Some kind of easy to carry easy to learn multiplayer game, like Uno. If you're with a group of your team members and your roaming the pit area, you'll probably find a down/bored looking pit eventually. You wouldn't believe how much they'd love to play a game of uno (or whatever else) with you.
Money for a MARTA pass if you're staying too far away from the Dome area. Also, bring a MARTA map with you if you're planning on going many places downtown to help you plan your route before setting out.
And I have to second a camera. You won't believe how hard it is to find a street without FIRST people on one or both sides of it.
See you all there! Two days!!!
-q