Idea for a Magic tournament: take a large pool of cards and divide them randomly among the contestants. [1] Each one builds a deck out of their cards, and they play a standard single elimination tournament. When you beat someone, however, you get their cards; every round you have twice as many cards to choose from when building your deck. In other words, when you defeat another wizard you gain their powers. There can only be one.

(If you are unfortunate enough to have a group of people that's not exactly a power of two, you will need to have some players skip a round. To keep things fair, give them enough more random cards to double their number. This is the same as imagining they beat someone else at their own level instead getting a bye.)

Update 2012-07-19: Dave Bonner points out that there's already a Highlander Magic variant in which "there can only be one" copy of each card. I don't think it's as good a fit for the name, but they got there first. So I should probably call this something else. Ideas?

Update 2012-07-20: On Danner's suggestion, I've renamed this "Borg Magic". When you defeat someone you add their biological and technological distinctiveness to your own.

[1] Magic has the problem that in standard play the amount of money you're willing to spend on it has a large effect on how well you do. [2] You build decks from cards you own, there's an economy around the cards based on how good they are, and to a large extent you can buy success. There are tournaments that try and deal with this in various ways, like having the contestants begin by drafting from a shared pool, and this is another approach along similar lines.

[2] From the perspective of a game designer this may not be a 'problem', and MMOs have learned from Magic's example in harnessing people's desire to pay money to do better, but it's not something I enjoy.