The Shrine

First, Serum Powder and/or cantrip frantically to acquire the cards needed - it can be a 5, 6, or 7 card combo - either Simian Spirit Guide OR Chrome Mox + any spell, Golgari Rot Farm OR both Simic Growth Chamber and Orzhov Basilica, Ad Nauseam, Amulet of Vigor, and Summer Bloom.

Play Spirit Guide->Amulet of Vigor. Play a green bounceland, tap it for mana before it returns to your hand, cast Summer Bloom. Play a black bounceland three times, cast Ad Nauseam. (Retain either 1 green or 1 white mana.)

Draw until you get white mana and Angel's Grace. (Try not to die!) If you used Orzhov Basilica to cast Ad Nauseam you can just cast it when it's drawn with the retained white mana. If you used Golgari Rot Farm your retained mana is green, you can draw into a second Summer Bloom and cast it using a Mox or a Guide, then draw into a white mana land, then cast it.

Play Grace, draw entire deck.

Drop and play other lands as necessary, using remaining land drops, to play remaining Summer Blooms and all Chrome Moxes, giving you many more land drops, play Laboratory Maniac using Cavern of Souls or Savage Summoning (probably not necessary, but still fun) and any appropriate blue mana source.

Play Gitaxian Probe with Laboratory Maniac out to win the game.

You even have plenty of mana, a Dispel, and Pacts of Negation to counter any instants they may actually be able to throw at you.

Smile while appropriately ashamed of oneself (then duck things thrown at you).