I'll also throw out... at one point I used a gmail calendar for my game. it worked very nicely and I even had it set up to send me reminders, so I was able to alert people about upcoming birthdays, events, etc. I embedded it on a wiki I had running for the game, but I'd imagine you could do so on an IJ page. It's not super customizable, but it's insanely easy to maintain and automatically updates for the current month.