Mono Green EDH (EDH / Commander)

Build an army bigger than the USA's, pump mana like you're pumping oil, buff elves like they are on steriods, give your creatures a boatload of p/t aaaaand you're gonna get divorced.

No seriously, that's all there's to it.
Omnath, Locus of Mana gets nice and fat as you ramp up that green mana using cards like Nykthos, Shrine to Nyx, Extraplanar Lens, Elvish Archdruid, Marwyn, the Nurturer, Priest of Titania and Wirewood Lodge (+ one of the elves).
Add Freyalise, Llanowar's Fury, Lys Alana Huntmaster, Imperious Perfect and Hunting Triad to get some extra Elves out and you got lots of mana to pump.
Buff Omnath, Locus of Mana some more using Timberwatch Elf and Immaculate Magistrate for some extra fun.

Drop down an Overwhelming Stampede and you can slap all enemies in the face with some 200/200 elves coming that way.
Seriously, I often have games where I just send a jackload of 500/500 elves with trample their way.

This deck struggles against boardwipes and card stealers, but if you have multiple opponents, just play Lifeblood Hydra with an Assault Suit and they should start hurting each other instead :)

Cards (and combos) I'm still looking into (not in any particular order):

• Voltaic Key + Doubling Cube + Rings of Brighthearth == Infinite Mana
• Vivien's Arkbow == searching for big creatures to play them early
• Vivien, Champion of the Wilds == Self-explanatory
• God-Pharaoh's Statue == Slowing down opponents + tickling them to death
• God-Eternal Rhonas == Very nice with (for example) Ghalta, Primal Hunger and Omnath, Locus of Mana
• Nissa, Who Shakes the World == passive ramp, ult is a bonus but will never pop anyways.
• Paradise Druid == Elf + emergency mana
• Band Together == To get rid of bigger creatures
• Challenger Troll == Make tramplers do even more damage, nearly guaranteed death of blocking creature
• Thundering Ceratok == Trample
• Kronch Wrangler == Get's out of hand decently fast