Two Card Combos

[Mlerner12]

Works better with a Laughing Troll

[TheRagingMage]

The {Niv-Mizzet, the Firemind} + {Curiosity} combo doesn't work, unless you want the game to end in a draw.  The loop would continue until you can't draw, and then state-based actions would be checked.  You're opponent should have 0 or less life, but you would have also attempted to draw a card when you're library was empty.  Therefore, you would both lose and the game would end in a draw.

[TheRagingMage]

{isochron scepter}
{time walk}
I has infinite turns at turn 3

That's a $907.97 combo.  For only one of each card.
Also, {Time Walk} is a sorcery and {Isochron Scepter} imprints a instant.

[MementoMori]

The loop would continue until you can't draw, and then state-based actions would be checked.

Both Niv and Curiosity have triggered abilities. State would be checked before each trigger resolved, so the only way to deck yourself is if your opponent has a ton of life. Even then, Curiosity's ability is a "may," so you can opt not to draw, ending the loop.

[Gorzo]

The loop would continue until you can't draw, and then state-based actions would be checked.

Both Niv and Curiosity have triggered abilities. State would be checked before each trigger resolved, so the only way to deck yourself is if your opponent has a ton of life. Even then, Curiosity's ability is a "may," so you can opt not to draw, ending the loop.

MementoMori speaks truth. +1

You could also target a creature with Niv-Mizzet's ping (Niv Mizzet himself if need be) to end the loop, as curiosity only triggers when damage is dealt to an opponent.

[TheRagingMage]

Now I see.  Should have read the card more.

[Destore117]

 {Sorin's Vengeance} +  {Final Punishment}
Little high mana cost but still :p

[TheRagingMage]

{High Tide} + {Palinchron} + at least 7 {Island}s = Infinite Mana!!!

[DrizztDoUrden]

 {Boundless Realms} +  {Primordial Hydra} = amazing

[TheRagingMage]

{Phyrexian Unlife} + {Melira, Sylvok Outcast}

[Bman0121]

{devoted druid} and {quillspike}

[Mattao19]

{devoted druid} and {quillspike}

That's a great combo

[KILLERBEE]

{isochron scepter}
{time walk}
I has infinite turns at turn 3

That's a $907.97 combo.  For only one of each card.
Also, {Time Walk} is a sorcery and {Isochron Scepter} imprints a instant.

instead of  {Isochron Scepter} you could use  {Panoptic Mirror}+ {Time Walk}

[Ageniv]

{Notion Thief} + {Time Reversal} = all opponents discard their hands and you deck yourself

[Mactitioner]

 {Kill Switch} +  {Mycosynth Lattice} = awesome fun in EDH