I just discovered DragonBox, an “Angry Birds”-like game that is all about solving algebraic equations.
It may sound boring but they’ve done an excellent job of presenting the math in the form of a puzzle so that you don’t even know you’re solving math equations until it’s too late. Instead of “x” and “y” you see cards with cute characters on them, instead of numbers they use dice, etc. This may sound subtle, but the result is that you turn off the part of your brain that says “this is school!” and just enjoy the puzzle until you are solving algebraic equations as if they were a puzzle, which is how it should feel.
You can read a more detailed writeup of the app here:
I highly recommend checking it out. It’s an excellent example of making math feel like something you’d like to do instead of playing Angry Birds. It doesn’t dress up the content too much, it doesn’t rely on competition or speed to engage you, and it doesn’t require a lot of explanation, allowing you to learn algebra exclusively through solving the puzzles, giving you a better sense of what algebra is really all about.