The UUURRR-Dragon (EDH / Commander)

This is a High Tide Storm/Combo Contol Deck.
It tries to ramp in the earlygame with mana-rocks, and ensure it's landdrops with cantrips. It generally tries to control the midgame with tons of interaction (Counterspells, Boardwipes, Targeted Removal, Bounce). Important: only use removal if nessecary! The life total is a big ressource in this deck, so it's ok to take some hits.
I think finding the right spot for casting Niv is the hardest part in playing the deck. If it is possible to ramp him out on tourn 4 I ussualy play him. But in any other case I never want to tap out in my turn just to play him. I usually want to keep up mana for interaction, and even if I can keep up mana I usually only cast Niv if I can protect him with a counter or two or if I have nothing better to do. I also don't care about getting Niv out early because the deck can definetly win without him as well.
It tries to win by either creating tons of mana with High Tide + Turnabout / Time Spiral, and in best case Niv-Mizzet, Parun on the field to keep the carddraw going, to storm off.
The typical wincondition while storming off is either trying to get an Aetherflux Reservoir or Sentinel Tower on the field, or even better having them before storming off. Also creatures like Guttersnipe, Firebrand Archer and Electrostatic Field do good amounts of Damage while storming. If there is an Aetherflux Reservoir, Sentinel Tower or even Guttersnipe on the field an overloaded Mizzix's Mastery can win the game as well.
As a backup Wincon, which sometimes can be assembeld pretty early in the game there is an Isochron Scepter + Dramatic Reversal combo in the deck. If Niv isn't on the Field it can Ramp into him and then draw the entire Deck with the Niv triggers to win from there with one of the Guttersnipe-like cards or Aetherflux Reservoir / Sentinel Tower. And before you deck yourself with the combo, Niv-Mizzet, Parun can kill himself with his triggers.

Nexus of Fate is mostly in here because of mill protection, although the extra turn can come in handy.

The deck also functions well on a cheeper budged:
Cards to cut would be: Time Spiral, Mox Diamond, Scalding Tarn, Force of Will and Mana Crypt - but Mana Crypt is definetly the best of those
Instead of those lots of cards could be played, but if you want to go more towards the Combo cards like: Fabricate, Gamble, Merchant Scroll, Curiosity, Ophidian Eye, Tandem Lookout would be good
The curiosity effects also work pretty good with Guttersnipe, Firebrand Archer and Electrostatic Field