Format idea.

[Mochalatte37]

I have a new format that I think would be a lot of fun to play.

Eternal night:
Basically it is played like any other game of magic except one twist. Your creatures get tired.

How to play: it plays out the same as standard but when a creature enters the battlefield it's toughness is replaced with "stamina".
When the creature does actions such as blocking or attacking it loses one toughness/stamina (all creatures have the ability "tap: creature gains one stamina") when it hits zero the creature taps and doesn't untap during the players next untap step, when untapped from "resting" it's stamina is reset and it has summoning sickness.

(Addition)
You can kill creatures while they are tapped by using cards that say "destroy" or "exile"

And creatures can only regain their stamina by it's tap ability, resting, or regenerate.

[Demigoron]

Is stamina and toughness the same thing them?  If so, does the creature lose stamina/toughness before or after blocking?  Also, could you raise a creatures stamina/toughness above the original amount?

Plus, doesn't that make anything with toughness of 1 entirely useless?

[Mochalatte37]

After blocking there is a effect phase which causes the loss of stamina. And yes toughness and stamina are the same thing.

Toughness can't be raised but it's strength can.

[Rass]

Vigilance is broken in this system.

[Condor-Wingman]

Imagine that in this format, werewolves would never transform back to humans. Also, cards like {Full Moon's Rise} and {Moonmist} would have extra combat tricks. What about these features, along with the Inspired keyword?

[DirtyMustachio]

Vampires get +1+1 after midnight