I ran a game on IRC a long time ago. The setting was stationary, so players could interact with each other even if I wasn't on to lead the action, and I had a few NPCs that I played through. I eventually handed the reigns off to a friend when I had to take a factory job that drained all my energy, and when I came back a few months later, it was gone. I've never been able to get anything like it together since, so I'm always looking around for people who are doing something similar. It was a blast.