On work time, specifically, only once: Fridau afternoon. Lass who I'd been having a casual colleagues-with-benefits arrangement had taken the day off. Got a text from her at lunch-time telling me her fiancee, who, I think, was high up in PayPal or EBay or something, had been called out to, like, Zurich and that she was in the pub around the corner with nothing to do and nobody at home for the next few days.
I immediately booked out my diary for the afternoon for a non-descript external meeting and pretty much ran to that pub with a smile as big Thierrno's last Saturday.