I use the campaign's internal forum and make a "Scheduling session for Tuesday May 26" thread title for each time we plan to play. (Actually I learned to combine the next 3 sessions into 1 post, and then make a fresh post after 3 sessions.) Not truly a calendar, just text and referring to the "Next Game Time" set by the GM on the Details page, which shows/confirms the appropriate time for each individual player's own time zone. So we don't have to talk about the time, and time zone conversions, we just talk about the Date and everyone's availability, and say "refer to the campaign details homepage for the time converted to your time zone". Also I put in the Scheduling thread, "RSVP regrets only" and players respond only if they have a conflict at the proposed game-day/time. If they don't reply it indicates assent. More visual, in-the-game table, what I have done on occasions is make a landing-page, splash page map, with Boxes for different days, or different poll topics. Players can enter the game table at any time during the week, and move their token into the box they are voting for (which could be a proposed game day, or move your token onto a visual calendar). To make blank calendar boxes, you could either use the Drawing Tool and text tool to write the captions, or search for May 2015 Calendar in the art search, or take a screenshot of an existing blank calendar (say from your computer's calendar), put that on the game table with a Token for each Player to move onto their favored times. Perhaps multiple tokens per Player if they can select multiple options/days/times.
