Obviously you have not heard of ultimates tic tac toe
Start by making a rather large tic tac toe arena
Once finished add smaller tic tac toe arenas within all the squares
Play tic tac toe as you normally would in the small arenas and once a player wins that square of the bigger arena becomes theirs and you win the game by having the on a row in the large arena (if the smaller games end i in a tie the square becomes neutral)
This game can also be expanded infinitely for maximum enjoyment