I love it when my kids go from “I’m bored” to “I’m making a board game”. This is one my older son prototyped with cardboard. It’s called Everest and the premise is that you’re part of a mountain climbing party trying to reach the summit.
The cool thing about it is that it’s a cooperative game so you’re not trying to battle each other. Each player has health, hunger and warmth points that go up or down based on cards you draw when you land on certain parts of the board. Even if your character dies, you can win the game if someone else on your team makes it to the top.
It’s kind of like a monumental Chutes and Ladders type of game only instead of playfully being sent down a slide, you starve, get hypothermia and get buried by an avalanche.