What if... you were playing chess in the dark?
I want to make a standard game of chess, but you can only see the board where your own pieces have line of sight.
It's not the most original idea, as I have just found out, but it's still a good starting project.
How much experience does your group have? Does the project use anything (art, music, starter kits) you didn't create?
I have a bit of experience with python, but haven't gotten myself to make a full project before.