Let's Do the Time Warp Again (Modern)

Pyromancer Ascension deck built around taking, essentially, infinite turns.

Card draw, card filtering, and cheap spells to get your GY filled and start putting counters on Pyromancer Ascension as soon as possible. Quick note at the outset: you WILL piss off a lot of people. 8 counters tends to do that.

Shivan Reef is, essentially, the budget version of Scalding Tarn, which is just so damn expensive. Pick whichever one you like. Although I frequently end games with <5 life, so you need to try to conserve as much as you can. It typically takes a few turns to get everything going, and I have a nice archive of games where the combo got off when I was at <10 life. I've got a couple where it didn't start until i was at 2 and i was dead next turn :).

Days undoing is in here to recycle your deck. Remember that if it you cast it, the turn ends. All spells, triggers, and abilities on the stack after it are removed. Nothing happens. There's no end step.

Keep a pen and paper handy because there's a chance you'll lose track of extra turns. My record as of today (2/10/16) is 15 extra turns before the opponent conceded. My single-turn highest gain is 7 extra turns in one turn.

Pro tip: a lot of people won't concede until you cast days undoing. I think it's because the deck usually has a good chance of decking itself in other forms.