The university I used to work for had a couple of those mandatory fun type of events, but at the very least they put out an email beforehand that said that it counted as work-time, and you were allowed to fill out your time-sheet as if it was a regular workday. My current job allows me to do the same, but also count in any commuting time that is longer than your average as "time worked", and since i live like 5 minuttes away, I managed to "work" like 9 hours from a 6 hour mandatory meeting, since it was far away from my office.