What are some of your favorite events on your forums to get activity going?

What are some of your favorite events on your forums to get activity going?

I like challenges. I like simple ones that have simple prizes, like digital badges.

Photo challenges, fitness challenges, writing prompts, etc.

Have any of you ever done this sort of challenge-posts on your forum?

I love seasonal events such as Easter, Christmas, Halloween. I love running those sorts of things.