MTG Combo: Archaeomancer + Deadeye Navigator + Walk the Aeons
This creates infinite turns, but requires at least 8 mana to do so. Simply have Archaeomancer (or any creature that can return a sorcery to your hand) soulbonded with Deadeye Navigator. Activate the flicker ability on Deadeye Navigator to blink the other creature to return any Extra Turn sorcery/instant spell to your hand and cast it. Repeat every turn.