Lethal Vapors + Grand Abolisher + Teferi's Protection
I've never tried to pull this off in a game, but its the funniest combo I know. I call it "win the game by removing yourself from it" or "how to play magic without playing magic"

You start with [[grand abolisher]] out. This is important to keep others from doing the trick you're about to do. Next you play [[lethal vapors]]. The important part of this card is the activated ability. You put 1 million copies of that ability on the stack, skipping your next 1 million turns. While those are on the stack, you cast and resolve [[teferi's protection]]. So now, until your next turn, your life total can't change, and you have pro-everything, and your next turn is 1 million turns from now. From here, the game plays out with other players as normal, until its down to just one. They continue taking turns until they deck themselves, then you win by being the last player "technically" in the game.

You can still lose to certain things like global mill effects, alt win con cards, or commander damage combined with "damage cannot be prevented" effects. Your opponent(s) can also get around your million turn decking strategy by having some way to infinitely shuffle one or more cards back into their library. If they do that, 1 million turns later, they will have a boardstate consisting of (theoretically) basically every permanent in their deck, and a perfect hand, and you'll have whatever you had when you did the combo, so you'll probably lose.

However, in "normal" circumstances, where your opponents are trying to win through some kind of damage and they don't have a way to keep from decking themselves, you'll win.

Bonus points if you pull this off in a game store, go join a different pod and start a game while you're technically still in the first one, and win the first one all while playing a new game of magic.
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Kaervek's Spite + Academy Rector + Barren Glory
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Caged Sun + March of Madness + Maskwood Nexus + Life and Limb
Animate a [[Caged Sun]] with [[March of the Machines]]. Make it a saproling with [[Maskwood Nexus]]. Make it a land with [[Life and Limb]].

Your Caged Sun is now a 1/1 Saproling Forest.

Now tap it for mana. This is where the fun begins.

Because Caged Sun triggers when a land you control adds mana, normally it doesn’t trigger itself, because it’s not a land while keeping all its abilities. However it is now, and it will add mana, then see that a land added mana, then Caged Sun makes mana.

Normally when Caged Sun adds mana it ends there because it wasn’t a land. But now, it’s caught in a loop adding mana to your mana pool. With infinite loops, you can respond and stop it potentially, else the game is a draw.

Here though, we have an infinite loop that adds mana, something that doesn’t use the stack. No one can respond to it because the rules say no one has priority until Caged Sun is done, but it never will be.

All players are stuck. No land plays, split second, nothing. You can’t even pass priority. Congratulations, you broke the game in a totally irreversible way. All while Caged Sun sterling engine is busy making infinite mana.
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