If you use curiosity to enchant niv-mizzet, the firemind would firemind's ability cause an endless chain dealing damage until you win?
Curiosity + niv-mizzet the firemind
This is an optional infinite combo. {Curiosity} says you MAY draw a card. You can halt the combo if needed, or make it infinite until you run out of cards to draw.
Awesome
One very good one to use with niv is {mindmoil}, have an artifact untap combo running with an imprinted {isochron scepter}, and you can buzz through your entire deck, especially if you play with {aluren} and many, many, low CMC critters.
You also have the option to target a creature (including Niv-Mizzet himself) to stop the chain, since {curiosity}-type effects require damage dealt to a player in order to draw a card. It'll keep you from milling yourself (should you use a non-"may" version of curiosity).