This doesn't seem like it would be that hard, but I think it would be incredibly helpful.
It would look like this:
[On Activate] [Self] [SetRandomEventEnabled][________________] <Where the number of events go.
This makes it so on activate, a random one of the events in the box is enabled. This would allow us to make zombies that randomley spawn items, and stuff like that.
And possibly, it would have a second output. heres an example:
[On Activate] [Self] [SetRandomEventEnabled][1 2 3 4 5] [10% 10% 10% 10% 60%]
This way, you set the chance that something will happen. But i don't know if that will work.