Welcome to DC, Deerme.
I think potluck weddings are a wonderful thing....it brings to mind the old days when weddings were truly a community celebration, and not the circus of poof and expense they have become. Can you give us more information, such as how many people your dish needs to serve, and have there been assignments about the type of dish to bring... (main course, appetizer, salad, desert?)
I sure hope the instructions were not to just bring a "dish", as that could be a disaster.
We'd love to help you.
Life is not measured by the number of breaths we take, but rather by the moments that take our breath away.