First of I have to say Game jam calendar is great thing to have. It helps to find gamejams and join them.
The problem is scheduling. It's hard to see currently what jams are starting right now, because they are not in any order. I wish I could sort them by time when they start, by their length and type and so on. Now they are a scrambled mess with no any order in the calendar table. I'm sure this can be fixed as I have made similar calendar of job resource allocations before. I think I have put this topic here before, but can't find it. maybe Itch.io is not bothering with this. If they had open api to fetch this calendar data, I wouldn't be bothering here and would do gamejam calendar myself. But I hope some improvement will be done. I don't know is this even right place to give feedback on this and does it get even heard, but i hope so.
About the scheduling, when you have fulltime job and not much time available in your hands to look up gamejams to join. It would be nice to be able to filter and sort them so you can find the best one that fits your available time. I don't want to join too short or too long jam or jam that doesn't fit my tools of choice.
Please feel free to give your suggestions here too on this game-jam calendar.