Arcane Bombardment + Temporal Manipulation + Clockspinning

Arcane Bombardment

Temporal Manipulation

Clockspinning

How it works

1. Cast Clockspinning with buyback by paying 3.
2. Arcane Bombardment triggers, exiling an instant or sorcery at random from your graveyard, and casting a copy of Temporal Manipulation without paying its mana cost.
3. Resolve Temporal Manipulation, causing you to take an extra turn after this one.
4. Resolve Clockspinning, returning Clockspinning to your hand.
5. Repeat each turn.