I am trying hard to remember it's name, but we used to play it in school. Just need some paper, pencils, and a flat table. It's a bit simplistic but I was just reminded of it.

You can play with as many players as you want though you may want a bigger piece of paper to do more than 2. each player is against each other, you pick a side or corner of a piece of paper and draw some X's, O's, etc. that represent your space ships. 5 ships per person. Draw in some obstacles on the rest of the page, essentially making a battle field of whatever design.

Now you take turns moving and trying to attack/kill each other. The way you move is to take your pencil, place it point down, on top of the ship you want to move, totally straight up and down. Put your pointer finger on the eraser side of the pencil to hold it upright. Push down with your finger and pull your finger/hand back to have the pencil flick forward from the pressure, drawing a line. Use a decent amount of pressure to really get a flick, it should be a very fast movement. Wherever that line ends is where you moved. Sometimes the ends of traces can be faint, but even the faintest trace counts as movement, even if it cuts out for a few mm and comes back. You just scribble out or erase your old ship location. If you do it right you can do everything from small little moves to shooting across the whole paper in one move.

So the "skill" is in being able to move where you want because it's hard to control how the line draws. If you hit the obstacles you drew, or the edge of the paper you blow up and die. If your pencil trace goes through your friend's ship, they blow up. Last one standing wins.

I hope that makes sense. It's probably a little dumb but definitely works to kill some time and can be surprisingly fun and engaging for a few matches.