This is a game that me and my friend would play during math class. We introduced the game to a few others and they were soon blissfully ignoring the math teacher as well. According to my friend, the game was originally published in some mathematics journal, but I haven't seen any evidence of that; if I do, I'll add it.

Setup

Take your graph paper (we used lots of paper and so we ended up stealing it from the school) and draw a race track ala Formula One. It should be about 5-8 squares wide and have some good turns. As you play the game, you get better at making tracks. Be sure to mark a Start and a Finish.

Each player (one to four seems about right) picks a position on the start line, placing a dot (his or her car) on the intersection of the graph lines. We liked to use different colors for our cars, but what can I say? We were math geeks.

Moving

A car moves with a vector. I don't think I knew what a vector was back then, but that's probably the easiest way to put it. Choose who will go first. We discovered that blind-folded knife fights were the best way to decide who would go first, but feel free to use your own method. A player can increase (or decrease) his or her speed by one graph unit in either the up/down or the left/right direction.

Each car starts with a speed of (0,0). So, for the first turn cars can be traveling either: (1,1), (1,0), (1,-1), (0,1), (0,0), (0,-1), (-1,1), (-1,0) or (-1,-1). Plot the car's new position on the graph paper and then draw a line from the old position to the new. If the line crosses a wall, KABOOM!

Example Movement:

Speed:   Change: Up(+)/Down   Left(+)/Right
------           ----------   -------------
(0,0)                 X             X
(0,1)                +1             0
(0,2)                +1             0
(0,3)                +1             0
(-1,4)               +1            -1
(-1,3)               -1            -1
(0,2)                -1             0
(1,2)                 0            +1
(2,1)                -1            +1
(3,0)                -1            +1
(4,-1)               -1            +1
(5,-2)               -1            +1

You aren't allowed to be in the same position as another car. You'll just have to pick another velocity vector, even if that means slamming into a wall.

To Win

The first car to cross the finish line wins. We usually allowed ties, but if you're more ruthless...

I realize it might be hard to understand the rules without pictures and all that. It's a fun game for physics geeks and it's easy to play. Use it to ignore your teacher today.