This is a FOSS alternative that looks decent for public events https://www.attendize.com/ but I feel like anything focused around "ticketing" will feel odd for small events. "Did you get a ticket for my birthday party next week?"
We pick up facebook events (also Eventbright and lots more) and show them on our app. Its not perfect yet but we are working on it. oh also i'ts free let us know what you think.
Sorry my misunderstanding. We are focusing on aggregating events from as many sources as we can but have no way to publish them yet. As mentioned Eventbright is good for free ticketed activities(and we show all of those as well).
I would feel weird getting a ticket for my friend's birthday party or backyward BBQ, but this does seem to be a decent suggestion for more public events. This looks like a decent FOSS alternative, though I haven't tried it https://www.attendize.com/