One thing to consider, perhaps the most important one, is that to have a calendar that lists all of the upcoming events (a worthy undertaking, IMO) requires one of two things:
Either a person or persons dedicated to constantly and continually maintaining and updating said calendar...
Or, an open calendar application that anyone can make entries into.
A calendar that is not updated regularly would soon be worthless. One that is polluted with trivial stuff would also.
Manually maintaining a calendar for perpetuity would not be a trivial undertaking. Ask Bungie, who took over the FJR Assisitance list. He converted that over to a user up-datable database in order to not have to constantly maintain and distribute / publish it.