I've never attended, but a co-worker of mine attended and made a hex based equivalent of a Sokoban game https://en.wikipedia.org/wiki/Sokoban. It was pretty fun to play, I'd probably recommend the game jam based on that alone.

On a somewhat related note, the games from DigiPen's senior projects are often pretty enjoyable: https://games.digipen.edu/. I'd especially recommend Narbacular Drop (predecessor of Portal, the game got the students hired at Valve), and Empyreal Nocturne (a sort of aerial combat game).