They design the board, write the rules, and then make you play it.
For ages6y - 12y
Time available60 min
Prep3 min
Mess
Noise
YouI will set it up, then step back
A long project that fills a whole wet afternoon and ends with something they can actually use.
What you need
a large sheet of paper or card
pens
a dice
buttons or coins as counters
How to do it
Draw a winding track of squares from a start to a finish.
Decide what happens on the special squares: go back three, miss a turn, take a shortcut.
Write the rules down properly, on a separate piece of paper.
Play it once. It will be broken in some way.
Fix the broken rule together and play again.
Most activity lists ignore the things that actually decide it
The valuable part is the second playthrough. Discovering that a rule they wrote makes the game unwinnable, and then fixing it, is systems thinking and revision in one. Writing rules clearly enough for someone else to follow is also demanding, precise writing.
Adapting by age
5 to 6 yearsYou draw the track, they decide what the special squares do.
11 to 12 yearsRequire a scoring system rather than a simple race to the end.
Keep it safe
None needed.
Cleanup tip
Keep it. Games they made themselves get played far more than you expect.