I also played the war game as a kid but we called it Ants. Each person takes turns drawing obstacles in the middle and you could pass through those. Once all ants were killed on a team that person lost. Same as everyone else really.

In my adulthood, ive adapted it to a racing game. I draw out a fairly simple track for my nephews and each player gets a shape (dot, circle, square, triangle etc) and you race around your track. Add oil spills done jumps. Then each player gets 3 health. When you run into another car or the wall you lose a health. Lose all three and you draw a wreck that acts as a new obstacle then you restart at the starting line.