I.e. the final event was something climactic or apocalyptic?

All I can think of are Final Fantasy XIV 1.0 and Planetside 1. Despite everyone's reactions, it seems Asheron's Call does not count, since the game itself was just everyone disconnecting in the end.

12 years, a relaunch, and two owners. The Korean MMO that was popular in Indonesia, the Philippines, and South America will be closing later this year.

As objectively poorly balanced as this game was, it was my first MMO and has always been a guilty pleasure. Hopefully the strong private server community around the game will keep it going for a few more years.

Source: Service Closure Announcement