In case you're interested in events that add traits, you'll see this is what I'm after, so there's some information scattered across the forum, you might have seen them before, but I tried to bundle them together.
First, check out (oh, I guess you have already!):
The tutorial by praguepride - it doesn't talk about events but it does go into adding traits.
http://forum.paradoxplaza.com/forum/showthread.php?586805-TUTORIAL-Adding-new-traits
It's pretty straighforward and a good template to work with.
There's more information over here, where you see me struggling over an event to add traits and some helpful comments from more experienced modders -
http://forum.paradoxplaza.com/forum/showthread.php?586721-adding-traits-does-this-seem-right
There's also me here, working on a (failed) event, the interesting thing is to check out the comments on the code (after the ###), so you have a better idea of things that could have been different...
http://forum.paradoxplaza.com/forum/showthread.php?587476-understanding-the-code
Of course, to see all this from an experienced modder's point-of-view would be ideal, but I guess most of them are hard at work with their own mods, so it's up to the new ones to struggle and post their finds here!

Just kidding... I do hope someone into programming/scripting can add more to this.