I used to have sex with my fiancee in the office of her workplace while she was on lunch. I'd bring her her lunch, then she'd make me crawl under her desk and have mine.
We did get caught by her secretary a few times, once while she had me tied to a chair. The secretary just winked at us and closed the door as she left. I always wondered if they could hear us in the Mayor's office (she was the city planner).