Execute Plugin init function one time Is it possible for me to execute any "init" like function for my Plugin the first time the user visits the site? You could say when the first userSession is defined.

I tried looking through the docs to see if there was any Event for when the user session is created but I couldn't find any.

I want to add some default values to the userSession the first time the user hits my site.
Sessions are initialized by Craft, and plugins are loaded/called after that, so you'll have to assume the session is already up.

Not sure about your use case, but here is how you could execute code once per session:

if(!craft()-&gt;httpSession-&gt;get('initialized'))
{
    /*
    Your code executed once per session goes here
    */

    craft()-&gt;httpSession-&gt;add('initialized', true);
}