Turn 3 Win

Ignoring concessions, how quickly can one win a Magic game? I mean number of turns. It is possible, apparently, to win on "Turn 0"- check out this deck or this one for that insanity- but I'm talking decks that are still legal (in any format). 

I can tell you only that I've won as quickly as Turn 3, using the following cards/tactics:

Turn 1: 

- play land + Gingerbrute

- attack with Gingerbrute for 1 damage

Turn 2: 

- play land + Syr Faren

- attack with Gingerbrute for 1 damage

Turn 3:

- play land + Titanic Growth + Giant Growth (both on Syr Faren)

- attack with Gingerbrute and Syr Faren (whose ability boosts the Brute) for 18 damage

Boom.

Of course, I pulled this off only one time. It was a combination of perfect card draw plus an opponent playing a control deck that hadn't gotten going yet. I don't anticipate it happening often, but it was fun to win so quickly.

This was an aggro deck; playing other types of decks (like mill or control) can take much longer. The fastest I've milled someone is turn 5.

Though these quick wins are fun, I'm glad they're rare. The fun of the game is suspense and interaction; games that end so quickly are a novelty but would quickly become annoying if common.