Citizens' Assembly no longer exists. We have the Senate, which is our regional legislature and makes the laws which govern our region (no real world RP, we actually follow those laws. hover over the laws dropdown in the taskbar at the top of the forum and youll get a list of links to our laws). You have to run for election to become a Senator. The next election is in about 10 weeks.
But we also have a place where we do write real world RP laws which we just set up, not that long ago. To join, post in this thread.
Following up on what Drecq said, it's actually your choice how much you want to get involved. You can do as much or as little as you would like, you just have to remember to post at least once in the forum at least once every 30 days to retain your citizenship.