For 2.5 years now, I've run Eastside's Hockey Elite Collide, a simulation hockey league that uses a program called Eastside Hockey Manager to simulate games. It's basically the same concept as OOTP or Strat-O-Matic for baseball.
We've had some difficulty filling a couple of our teams, but 25 of our GMs are core guys who have been around for quite a while. The league sims right along with the real-life NHL schedule, so you will always know when you have a game. I also enter the real-life draft class into the simulator every year. Realism is our biggest goal.
You serve as the general manager of a team, making trades, managing your roster, putting together lines, and communicating with other GMs. Real players and prospects are on every team and you have control over your draft picks.
We have a strict rulebook, basically our personal CBA, that mirrors the NHL's with a salary cap, waiver rules, a system for new contracts, everything.
Our current open teams are Minnesota, Boston, Vancouver, and Ottawa. It's completely free, from the software we use to joining the league. It's a really great time and gives you something to do throughout the winter.
If anybody's interested in learning a little more, just post here and let me know or shoot me a PM.