It's organised by work, but it's not work and there's no pressure to attend.
It's a slightly educational/cultural thing on a topic I am very interested in.
However, it's on my day off (part time) and I've already made an excuse not to attend a fairly important meeting that day. I don't like swapping my days and resisit it where possible, but I would have changed for this meeting, I genuinely can't this time.
However, the thing is in the evening and I could get there, but would have to pay commuting costs on a day I would otherwise not be going into town.
So, I think I'd enjoy it and it might look good that I've made the effort, or it might just highlight the fact that I didn't make the effort for the meeting?