What is the "Events" category for?

self-explanatory.

maybe for talking about events. ( duh )

What kind of events?

Maybe events such as Snap Con?

No, they make a separate category for that.

I think the idea is to move things like the Snap!Con categories into Events. Iirc, what's standing in the way of that is a limitation in the forum software on the depth of subcategories.