As a bartender I would love to have this hanging behind me in every bar I work in from now until the end of time. Just pure perfection.

I guess in a proper rules sense. Exile all spells, you may cast those spells this turn without paying their mana cost. If a spell has an X in it's cost X is equal to 0.

Hindsight would be an instant that let you reorder the stack and choose new targets for each spell. Make it a 20 cost spell that costs less for each card in your graveyard and unresolved spell this turn.