This is the third installment of the Monthly Topic Challenges with topics suggested and voted on here. This month's topic is "pencil-and-paper-games" (suggested by bobble) and will span from the 1st of September to the 30th of September. During this period, we will compile the list of relevant questions and post it as an answer to this question.
In the meantime, please go and propose and vote on future challenges!
Everyone have fun, and happy puzzling!
Link to other Monthly Topic Challenges.
The suggestion is copied to this post for posterity.
Throwing a purely tag-based one in...
Games meant to be played with a pencil and paper tend to be simple little time wasters. But that doesn't mean they can't be incorporated into puzzles in interesting ways! Their very simplicity means puzzles with them can still be easily understandable/accessible even if a little more complex.
This challenge is to create a puzzle deserving of the tag, or a related one like tic-tac-toe, even if using it would be a "spoiler" - so an enigmatic-puzzle which is edited into the list of challenge puzzles after a solve is perfectly fine. Puzzles would be about the pencil/paper games (strategy etc.), simply incorporate ideas/rules from them in some way (e.g. a Sudoku which has a Dots and Boxes variety rule), or involve such a game in some other significant part of the solve process.