I always tell people that together my husband and I are impossible to feed. That isn't really true, since we do manage to eat every day, but I am a lactose-intolerant pescatarian, or as I call it, a vegetarian who eats fish but no dairy to speak of, while my husband is a meat-eater, but can't have any hot spices. It's not that he dislikes spicy food, it sends him to the emergency room.
We got a party invitation. My first thought when I get an invitation is "yay! party!" My second thought is "will there be anything I can eat?" So I offered, along with pretty much everyone else, to bring something for the party.
We've never gotten together socially with this couple, but we like them. Our connection is music -- Kevin and I are in the same music organization. They live about 45 minutes away from us. All of this information goes into the decision about What to Bring. The party isn't for another week, but if I don't start thinking about what to make, it'll be store-bought hummus and pita chips.
I have a tasty recipe for stuffed mushrooms, but they'll be cold by the time we get to the party after the long drive. Maybe I could heat them up again at their house? Bruschetta? Likely to fall apart on the trip to their house. Dip? Boring. Maybe a salad? I have a delicious Asian salad recipe. Maybe I should bring two things. What about a dessert? Too many times I've been surrounded by delicious-looking dairy-based desserts. I could take care of that by bringing a nondairy dessert.
Look through cookbooks, search online. I have a week to figure this out.