Extra Turns deck loosely based on one that won a tournament years back. The goal is to hit the right cards and, when the time is right, start taking a bunch of turns in a row to kill your opponent(s) without giving them another turn. Full disclosure, this usually only works if the table doesn't know or realize the deck you are playing. Once you take 25 turns in a row and kill 3 opponents without passing turn nobody wants to sit through that again.
Without any creatures, this deck can be slow to get going, but the 4 copies each of the 2-cost Prophetic Prism & Kaleidostone are cheap to cast and give you card draw. Howling Mine is kind of a double-edged sword, but it is really helpful in getting key combo cards in hand quicker. This gives especially big card advantage if you keep it on the board when taking multiple turns in a row. You can use Sleep and Pollen Lullaby to help subdue attacking opponents and stall for time until you can take some extra turns. This is accomplished with another key artifact called Time Sieve. You have to sac 5 artifacts to activate it, but that is where Open the Vaults comes in. Another double-edged sword, this card returns all players' artifacts and enchantments from graveyard to battlefield, but it's necessary to keep reusing the Time Sieve. Time Warp is also in the deck to give even more extra turns. Unfortunately, Open the Vaults only returns artifacts and enchantments to the battlefield. That means you only have 4 copes each of Time Warp and Open the Vaults. I tend to play 2-4 player matches, so I stuck an Elixir of Immortality in the deck. If you are in a situation where you are running out of cards to draw or you've played all your key instants/sorceries, you can activate it to put them back in your deck. It also gains you 5 life and has saved me in a pinch. One win condition I like to use is Door to Nothingness. It does have a high activation cost of 10, requiring all 5 colors, but this deck fuels that with fixing and ramp from cards like Kaleidostone, Prophetic Prism, and Composite Golem . Lastly, there is Tezzeret the Seeker. His abilities work pretty well with this deck. His +1 can untap the Time Sieve to stack another turn or the Borderposts for 2 more mana, his -X can fetch an artifact and put it directly into play, and his -5 is how I like to finish my last opponent if facing more than one. Crack a Time Sieve, Open the Vaults, pass & start next turn, -5 from Tezzeret and the field full of artifacts you pulled from the graveyard last turn is now a whole army of 5/5 artifact creatures to swing for lethal. There are so many variations you could build on this deck and many strong newer cards, including enchantments that create infinite turns combos with cards in this deck, but I don't see the need to change it at this point. If you enjoy hearing your friends groan about you taking too long on your turn(s), maybe build one for yourself. lol
