Ask HN: Modern, ideally hosted wiki engine for small-ish community?

Apparently it's hard to find a software for a small community's knowledge database. I guess wiki-like engine is ideal, but which one? Confluence is very complex and enterprise-oriented, wikia is all ads and doesn't have any access control as far as I know. Everything else I found is either expensive or abandoned. What would you use to host common knowledge of a small community (think sports club)?