But two easy ones are 7-layer dip (refried beans with taco seasoning mixed in, topped with guacamole, topped with sour cream, topped with chopped green chiles, topped with chopped tomatoes, topped with chopped black olives, topped with shredded cheese) and tortilla rolls (mix cream cheese, salsa and black olives; spread on a tortilla and roll up. Wrap in plastic wrap and let set in the fridge for at least an hour. Place 4-5 toothpicks in each roll, then slice into bit sized pieces between the toothpicks).
I guess since it's an office function, Margaritas are out of the question...