The thing that always goes first is tortilla roll-ups. Take some softened cream cheese, add green chiles from a can and a little salsa, spread over flour tortillas, roll up, wrap up in plastic wrap, refrigerate, take to party, unwrap plastic wrap, cut into 1-1/2" pieces, serve with salsa for dipping. I can never make enough of these. Deviled eggs are a very close second, though.