Forge Beta: 11-01-2013 ver 1.5.4

[gos]

I discarded a Fiery Temper to Kindle the Carnage. I declined to use the Temper's madness ability, but the Carnage did no damage to any creatures.

[Marek14]

It's possible to cancel "return to hand" effect of Stormfront Riders.

Cards with optional untap triggers, like Leonin Battlemage, shouldn't ask you on resolution whether to untap them or not if they are already untapped.