Just a short one here, inspired by last weekend's get together.
This play variant was spawned some time ago when, in a 5 player game, I died early and was too impatient to wait for the game to finish, so I asked if I could reenter the game with a new deck. The next person who died asked the same. And so we just had fun running a marathon game of magic, and if you're ever looking for strictly fun, I suggest you do this too.
Problem was, we made a mistake. We started applying rules to the format. We came up with obnoxious tempo-enhancing things and a score system so there could be a winner at the end of the night and blah blah blah. We couldn't agree on anything, the rules kept changing, even mid-game, and we got real sick of it real fast, which was too bad because that first time was just too much fun.
While I'm sure some of you have tried similar things before, last weekend we revived the format with simpler rules. If you like the idea of a marathon game but you want a clear winner/more balanced system for the poor guy reentering an already developed game, here's the much simpler system you can use.
1) Whenever a player loses, they change decks and reenter the game, but they sit out for a whole round. In other words, skip what would have been their turn once, then let them reenter the game.
2) When a player reenters the game, their starting life total is the sum of all other player's life totals. This compensates for being many turns behind the other players. (You may want to put an upper limit on it however. Say 50 or 60).
3) Alternate win conditions have no effect.
4) A player wins the game by killing each other player once before dying themselves. This doesn't mean they have to clear the board of players all at once to win, it just means that they've taken each player out at least once with the same deck.
Unfortunately, this system can end faster than you'd think. Often times the winner wins using the deck they started the game with.
Hey, if you just want an endless game, but want some balancing factors, you could use the life total mechanic, (or not; it can feel inappropriate sometimes), and simply say that if a player can manage to defeat each other player with the same deck, they leave the game and reenter with a new deck. This can prevent a mass lock-down deck from sucking all the fun out of the evening, but with out banning said lock-down combo from being played.