It's the Magic: Cubic Leagues

My favorite Magic format is the Cube Draft. There's only one of each card, you can manage what unfun cards are or aren't in it, it's multiplayer by default, it negates fiscal and net decking advantages; it's just tops.

However, it occurs to me that its stable format allows for a different type of play; true League play. Most of you are familiar with fantasy sports leagues, where you measure the performance of players throughout the season and the victory of your imaginary team is affected by the performance of real-world players over a season. In some leagues, a computer game like Madden is used to that players can focus more on the trading, buying, and the interactive portions of the game.

The Draft
A Magic Cube league would incorporate many of those ideas. The players pull their three 'booster packs' of fifteen, and draft as normal (taking one from their pack, then passing the pack to their left or right until all cards are chosen).

The Season
After The Draft, each player makes a 40 card deck out of his or her drafted cards (their roster) and there is a series of games (most likely multiplayer, but some one on one as well) constituting The Season. A player's deck may change between games as they switch out cards from their roster.

Trade, Recruiting, and Retirement
At the end of The Season, players can try to shuck off some of the cards that aren't pulling their weight. Each player can offer up to twice their ranking - 1 cards from their roster (1st place can offer 1, 2nd place can offer 3, 4th 5, 5th, 7, etc.).

Trade
Players discuss any terms of negotiation for trading offered cards. It doesn't have to be 1:1, but any trades made exist within the game and are binding (ie, you can't offer money, nor can you offer a future service (such as the forfeiture of a game) and renege later.). After Trade, players return any untraded cards they want to keep to their roster.

Recruitment/Retirement
Then Recruitment begins. Recruitment is basically another draft, with all offered cards being retired and a new card being recruited for each retired card. Seating places the player with the highest (numerical) ranking is the first player, with the next-highest (numerical) ranking on his right, descending to the player ranked 1st.

A regular draft begins, save for a few additions:
-There is only one booster, with one card in it for each card being retired.
-First player 'opens' and takes first pick, then passes right.
-Direction does not alternate, as there is only one pack.
-A player cannot draft more cards than they have retiring, and only takes one pick at a time.
-A player may opt not to pick during a round, but must pick to end recruitment.

Replicants
Once per season, starting with the highest (numerically) ranked player, a player may suggest that one of their offered, untraded cards is a replicant. Only one card may be suggested as a replicant. That player recruits normally and at the end, instead of being shuffled back into The Cube with the rest of the retired cards, the replicant is removed from the cube and a new card of the same color, from the same collection, suggested by that player, and ratified by The Cube owner, is shuffled in to replace it.

Optional(ha-ha!) Rule: Ante
Play some or all Cube League games with ante. Losers simply recruit the difference as if it was a retiring card and the winner gets additional (mandatory) offers for their spoils(which will be retired if no one trades for them).

Example: Arthur, Bruce, Clark, and Diana play a league game and ante up. Bruce wins, and has a roster with three extra cards while Arthur, Clark, and Diana are each short a card on their roster. Whenever Trade starts, Bruce offers his maximum of one of his cards for trade (2x1st place-1), plus the three he won for ante. Arthur is 4th and can offer up to seven cards, but only puts up one. Clark offers no cards. Diana offers two. No one trades, so recruitment begins. 

All seven offered cards are retired. A booster of seven cards is drawn out of the cube. Arthur was 4th, so he is the first player for recruitment. He takes one card (his limit), Clark has no retiring cards, so he's playing Wii and Diana is the next player. She takes one card and passes to Bruce. Bruce takes the first of his four picks and passes back to Diana (Arthur's completed all of his picks so he's out, and likely playing Wii Sports or something). Diana takes her second (and last) pick and the other three are Bruce's.