Also, Jesse, don't forget an umbrella or rain jacket. They are forecasting rain and high's in the upper 60's...
Don't forget your state licensed id- for pickup at will call and for buying drinks after hours (or maybe during hours depending on your mood).
I'm also bringing raisins and pretzels for my purse to avoid really bad con food, for those long days of going from line to line.
Cell Phone and the Charger!
Not just clean underwear- but a pair of undies for EACH day, and maybe a spare one or two in case of fountain hopping, pool jumping, etc.
Toothbrush and toothpaste- because mints aren't enough... and floss is good, too