Choose from three spells. Call them Expelliarmus, Immobulus, Stupefy (or whatever). But really it’s rock, paper, scissors.

Swipe left to right on your phone to add a jolt of whatever spell is selected. This moves the “center” 10 pixels towards your enemy if you’re using the same spell, 5 pixels if you’re using the weaker spell, 15 pixels if you’re using the stronger spell. Of course, your opponent is moving the “center” the opposite direction at the same time, following the same rules.

You can switch between the spells at any time, but time spent switching is time not spent swiping.

The idea is to push the “center” of the beam all the way to your opponent, where he takes damage and the center is reset. Take damage three times and you lose.

It definitely would work much better with Harry Potter characters and spells, possibly a marketing tie-in to Deathly Hallows part 2.

Add sparks and glows and all manner of cool sound effects and special effects. Include sound bytes from the characters battling.

Make one kid ridiculously happy.