This is my Niv-Mizzet deck that is one of the 2 decks I have been playing to win the most recent season of the EDH league that I play in at Armada Games. I'm sure a decent number of people read Sheldon Menery's EDH articles on Star City each week and if you've seen him mention playing against David with Niv-Mizzet that would be me and this deck. I'll post my other deck, Omnath, that I alternated each week with in another thread. I listed this as casual cause the Armada league tends to run towards games that are very interactive and take a while and hopefully as little combo-ish as possible. Ni-Mizzet can easily be built as a combo deck but this is not that and is really a control deck and should be played as such and if played right can always win.
1 Niv-Mizzet, the Firemind
Blue Creatures
1 Gilded Drake
1 Lighthouse Chronologist
1 Trinket Mage
1 Cryptoplasm
1 Kira, Great Glass-Spinner
1 Thada Adel, Acquisitor
1 Vendilion Clique
1 Glen Elendra Archmage
1 Sakashima the Impostor
1 Sower of Temptation
1 Venser, Shaper Savant
1 Azami, Lady of Scrolls
1 Teferi, Mage of Zhalfir
1 Keiga, the Tide Star
1 Draining Whelk
1 Arcanis the Omnipotent
1 Inkwell Leviathan
Red Creatures
1 Taurean Mauler
1 Viashino Heretic
Artifact Creatures
1 Solemn Simulacrum
1 Duplicant
Colorless Spells
1 All is Dust
Blue Spells
1 Ancestral Vision
1 Pact of Negation
1 Brainstorm
1 Mystical Tutor
1 Trickbind
1 Counterspell
1 Mana Drain
1 Twincast
1 Rhystic Study
1 Capsize
1 Hinder
1 Last Word
1 Rite of Replication
1 Bribery
1 Desertion
1 Evacuation
1 Force of Will
1 Treachery
1 Future Sight
1 Time Spiral
1 Shattering Pulse
1 Into the Core
1 Insurrection
1 Fault Line
1 Starstorm
Artifacts
1 Relic of Progenitus
1 Sensei's Divining Top
1 Sol Ring
1 Izzet Signet
1 Lightning Greaves
1 Sapphire Medallion
1 Sky Diamond
1 Coalition Relic
1 Darksteel Ingot
1 Darksteel Plate
1 Oblivion Stone
1 Gilded Lotus
1 Mind's Eye
1 Mindslaver
Lands
1 Academy Ruins
1 Ancient Tomb
1 Boseiju, Who Shelters All
1 Caldera Lake
1 Cascade Bluffs
1 Faerie Conclave
1 Forgotten Cave
12 Island
1 Izzet Boilerworks
1 Lonely Sandbar
1 Maze of Ith
1 Minamo, School at Water's Edge
5 Mountain
1 Mystifying Maze
1 Reliquary Tower
1 Scalding Tarn
1 Shivan Reef
1 Steam Vents
1 Strip Mine
1 Temple of the False God
1 Vivid Creek
1 Volcanic Island
1 Wasteland
My other decks:
Omnath, Locus of Mana
Zur the Enchanter