Voronoi Tessellations

http://wonderfl.net/c/iNy0/fullscreen

Very cool! Make your own Voronoi tessellations with this interactive feature.

TwinCol

Games for your brain, indeed... and also addictive! Follow the squares of colors and patterns, and match them up by clicking on pairs. Seems easy enough, right? Try getting up to level 6, where the squares are moving across the panel at a fast pace, and intersecting with each other. Careful; some colors may look alike, but will have different patterns.

http://www.gamesforthebrain.com/game/twincol/

Math Apprentice

In these middle and high school math games, students will have the opportunity to learn all about math applications in real-world scenarios, from running a restaurant, designing video games, building theme park rides, choosing an art career, and more. The various choices here provide an excellent introduction to how useful math can be.

http://www.mathplayground.com/mathapprentice.html