One of the reasons that Legacy is awesome is that there are multiple manaless or near-manaless decks that see play, with this being the newest one. Dredge is the most-played manaless deck, and one- or two-land Goblin Charbelcher makes the rounds as well, but Oops, All Spells! is definitely the coolest. With the release of Gatecrash, two specific cards provided enough incentive to play zero lands, and both are members of the Dimir guild.
Undercity Informer and Balustrade Spy will mill your entire deck, assuming you have declined to add any lands, which may not sound great, but is actually an instant win. You end up with four Narcomoebas in play, which lets you then flashback Cabal Therapy to make sure the coast is clear, and then flashback Dread Return on Angel of Glory's Rise. The Angel brings back Azami, Lady of Scrolls (of Commander fame) and Laboratory Maniac, after which you tap Azami and win the game. You even have extra Cabal Therapys in case you need to put a combo piece you've drawn into the graveyard, or if your opponent has multiple relevant spells.
The deck basically just needs two things to go right: draw one of the eight Informers or Spies, and a way to make four mana (one of which is black). To that end, just about every free-mana source in the format is in the deck, including such convoluted engines as Summoner's Pact for Elvish Spirit Guide. The deck also has four Street Wraith and four Gitaxian Probe, making it a fifty-two-card deck.
I like the sideboard too, as it sides into Goblin Charbelcher and Lion's Eye Diamond, along with Spoils of the Vault. It may seem like the same sort of thing, but the idea is to dodge graveyard hate, which most opponents will have.
This deck kills turn one a good amount of the time and has to mulligan pretty aggressively to ensure that. It has a surprising amount of mana, so keeping hands that are just a mana short probably are decent, although hands without Informer or Spy and no Probes or Street Wraiths don't seem great. It's definitely a different type of Magic, but it finished well at a recent StarCityGames.com Open, and will at least give you plenty of time in between rounds!
Jeremy Barbeau's Oops, All Spells!
a:24:{i:0;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:18:"Undercity Informer";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"4";}i:1;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:14:"Balustrade Spy";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"4";}i:2;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:21:"Angel of Glory's Rise";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"1";}i:3;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:17:"Laboratory Maniac";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"1";}i:4;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:13:"Street Wraith";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"4";}i:5;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:10:"Narcomoeba";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"4";}i:6;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:19:"Simian Spirit Guide";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"4";}i:7;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:11:"Wild Cantor";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"1";}i:8;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:22:"Azami, Lady of Scrolls";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"1";}i:9;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:19:"Elvish Spirit Guide";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"4";}i:10;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:11:"Tinder Wall";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"creature";s:10:"deck_count";s:1:"1";}i:11;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:14:"Gitaxian Probe";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:7:"sorcery";s:10:"deck_count";s:1:"4";}i:12;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:12:"Manamorphose";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:7:"instant";s:10:"deck_count";s:1:"4";}i:13;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:15:"Summoner's Pact";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:7:"instant";s:10:"deck_count";s:1:"3";}i:14;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:12:"Dread Return";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:7:"sorcery";s:10:"deck_count";s:1:"1";}i:15;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:10:"Chrome Mox";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"artifact";s:10:"deck_count";s:1:"4";}i:16;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:13:"Cabal Therapy";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:7:"sorcery";s:10:"deck_count";s:1:"3";}i:17;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:12:"Cabal Ritual";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:7:"instant";s:10:"deck_count";s:1:"4";}i:18;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:11:"Dark Ritual";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:7:"instant";s:10:"deck_count";s:1:"4";}i:19;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:11:"Lotus Petal";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"artifact";s:10:"deck_count";s:1:"4";}i:20;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:18:"Goblin Charbelcher";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"artifact";s:10:"deck_count";i:0;}i:21;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:19:"Spoils of the Vault";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:7:"instant";s:10:"deck_count";i:0;}i:22;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:13:"Grim Monolith";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"artifact";s:10:"deck_count";i:0;}i:23;O:8:"stdClass":3:{s:9:"card_meta";O:8:"stdClass":2:{s:5:"title";s:18:"Lion's Eye Diamond";s:22:"field_card_image_front";a:0:{}}s:4:"type";s:8:"artifact";s:10:"deck_count";i:0;}}