If you can write a few paragraphs in just a couple of minutes, or have short little breaks in the course of a day to poke your e-mail and edit a growing post, it may be a good genre for you. The best part? Pirates can't backstab your character while you're AFK!

Anyway, the two I have gotten involved with are free form Star Trek fanfiction games.
http://www.firstera.net/ -- Based on the Enterprise series (22nd century, my favorite!)
http://www.sixth-fleet.com/ -- Game year is 2384 right now, continuing the TNG, DS9, Voyager timeline.
Just in case anyone might like to try them out.