Hey Inle! You are right, Game Jams can be sooo much fun... There is a Pizza GameJam currently going that I would like to partake, 3 days left, so it is a rush... Game to join? I got a base of the game going... but stuck.... Let me know if you would like to chat.
Sure, yeah no it is on GameJolt.
http://jams.gamejolt.io/pizzagames
It aint as alive as itch, but still a nice place to get going at.