If you like math, puzzles or winter sports, you need to play Sinerider, a sledding game where you transform the slope with math equations.
Created by Chris Walker, Sinerider asks you to send two little stick figures tobogganing down a slope that you can tweak, bend and flip by entering different mathematical functions. Your goal is to gather a series of white blocks, sometimes in the right order and sometimes in the right amount of time.
If you remember playing games in your graphing calculator, so does Walker -- the many hours he spent messing around on a TI-86 were the initial inspiration for the game. "It's this weirdly universal experience for geeky people with graphing calculators," said Walker at the Experimental Games Workshop in March. "I learned more from the calculator than many of the classes I had it for."
If you haven't messed around with algebra since high school, I strongly suggest you begin with the tutorial, a simplified reminder of which sorts of equations make which sorts of curves. While I'm no math whiz, I took high school calculus but promptly forgot everything, and this is perhaps the first time I've felt motivated to remember.
The game promises that it will "make you see math the way mathematicians see it: a creative process of exploration and discovery." Although it begins with the sort of algebra taught in a 7th grade curriculum -- and moves through topics typically taught in high school --- Walker says that even elementary students should be able to play with the help of a parents.
On the flip side, there are also more difficult puzzles that could even stump professional mathematicians. And because can make your own custom levels and send them to friends, "there is no limit to how hard new puzzles can be." (You can play the game in your browser, or download for Windows, OSX or Linux.)