Time Warp in exile (Time Warp exiled by Arcane Bombardment).
Arcane Bombardment on the battlefield.
Whim of Volrath in hand.
({2} magic symbol) ({U} magic symbol) each turn available.
Steps
Cast Whim of Volrath with buyback by paying ({2} magic symbol) ({U} magic symbol) .
Arcane Bombardment triggers, exiling an instant or sorcery at random from your graveyard, and casting a copy of Time Warp without paying its mana cost.
Resolve Time Warp, causing you to take an extra turn after this one.
Resolve Whim of Volrath, returning Whim of Volrath to your hand.