Two celebrants, less than a week to plan, and a venue where partying is technically off-limits. Those were the circumstances we had to deal with and given those, the best theme for such is a fiesta! A theme that is easy to pull off from the decors, to food, to drinks, and the music too! You just need a few elements to help set the festive mood, most of which, I'm sure you already have at home.
So when planning for a themed party at the office-- throw a fiesta and your co-workers are sure to forget they want to siesta!