I wish there was a site where you could register pick-up hockey for participants, list the times, fees, max # of players, and it would have checks in it like monthly verification by the person who registered the pick-up event for that date, time and location (so you know it's not a stale posting).
Ideally you'd like all the participants to register and pay in advance online but typically whoever shows up for pick-up hockey is whoever doesn't have emergencies / last minute commitments on that date or whoever remembers.