I will be attending a lecture and book-signing at a university in downtown Philadelphia. I'm going with my wife. We're taking the train. I will not have access to any goodies I have stashed in my car.

I will be carrying one of my shoulder bags, mainly for first aid items and a bottle of water.

I could get away with blue jeans and a sweater, but I'm dressing up a bit. My outfit will be khakis, a turtleneck, and a blazer. Keeping in mind that the pockets in both khakis and blazers tend sag quickly, what woud you folks carry for such an occasion?

I have some gear in mind already, but I wanted some suggestions in case I've forgotten something.

-- Craig