You could always go for those fake tux t-shirts ; o) At the last wedding I attended they handed out little black and white disposable cameras so that all the guests could take pictures, free photographers! It felt nice being able to sort of take part in the ceremony, and at the end of the wedding you put all the cameras back on a table for them to develop. I think people worry too much about things that just dont matter, people go to weddings to see two people they care about make a life long commitment.
Dont stress about the cake, the food, give them free food and beer and they will be happy. Certainly have a nice water supply you could hand out those little cheap mini hand held fans, anything to make people more comfortable. Of all the foods I have been to it was never the food, music or cake that made it special, it was the people. Remember the breathe and laugh. Surround your self with great company and you will have an amazing day.