I've been thinking about
Repercussion as a sideboard card against creature-based decks, instead of Searing Blaze or maybe in addition to it (in Kyle's deck, in place of the Volcanic Fallouts). I like it over Fallout because it gives you a more solid answer to decks whose creatures are frequently pumped over 2 toughness (merfolk, zoo, etc). In an aggro-heavy meta, you can drop most of the creatures maindeck in favor of Flamebreak and Magma Jet (Flamebreak should be obvious, Magma Jet to increase the likelihood of hitting your third land drop or sweeping the board when it's most relevant), with a few copies of Repurcussion in the SB. Drop some combination of Sulfuric Vortex, your remaining creatures, and Price of Progress, side in the Repercussions and Searing Blaze, and go to town. As soon as Repercussion hits, assuming you get to untap and no extremely unlucky draws occur, you're almost guaranteed to win the race...and going t3 Repercussion, t4 Flamebreak is hilarious. Turn 4 wins when a zoo player thought he was going to be able to race with his god hand are hilarious, as is hitting a Goblins player for 15+.
It might be too slow, it might be too fragile, but I doubt anyone's really expecting it, and the few games I've played with friends suggest that it can really break open an aggro-heavy meta.