Hi Kathleen, you can contact anyone who has posted privately in two ways. At the bottom of their post, you'll see an email and a pm button. The email button would send the person email, and the pm button sends them a private message here on the message board. (At the top right of the screen, you see a message that says "You have 1 new private message" or something like that, and you click on it.
To come to a co-op event, you could contact Julie in membership at firstname.lastname@example.org. She can give you information on what's coming up.