There is usually a themes, to inspire people. Here are a few we've had:
Appetizers and salads
Fresh from the Oven -- anything baked
Think Spring (having it this month) -- anything colorful, fresh or appropriate for Lent or Easter
I have some ideas for themes for the future, including a picnic. I am telling you all this because Joe thought some of my ideas were cheesy or something, so he started suggesting themes of his own:
Farm animals (this ham used to be a piggy!)
Food you wouldn't eat unless you were starving
For the last one, he suggested I just tell everyone to come hungry.