When you click on a day in this calendar (including in other months), a new wiki page is opened to create your event. Replace the name of the page from "Event Title" to the the name of your event (likewise in your responses). Use the responses to announce participation (as you join) or to comment in general.
Edit the wiki-page and add to it the links to your pages from other platforms, such as in facebook or google etc.
Use Tor from https://www.torproject.org/index.html.en for a true Anonymous.