Coordinate Grid Game: Looking for the Top Quark!

In Grade 5 Number Corner, "The Mystery Grid Game" (Computational Fluency, October) captures the attention of students as they search for arrays hidden on a 10 x 10 grid. If you'd like to extend the fun a bit, consider this online game, "Looking for the Top Quark!" From the site:

"In Looking for the Top Quark, each player receives six quarks that they hide on a grid. The players use coordinates to find their opponent's hidden quarks. The first player to find all six of their opponent's quarks wins!"

Students can play on grids of varying sizes, against the computer or against another child. Grids include negative numbers.

Have a favorite online math game to share with fellow educators? Let us know.