Flame on! is a mono-Red Ritual deck that abuses the interactions between Past in Flames, Pyromancer's Swath and Grapeshot. The deck casts Ritual-effects, such as Rite of Flame and Pyretic Ritual to generate mana, then casts either:

a) Pyromancer's Swath and Grapeshot; or
b) Double Grapeshot.

Also included, as an alternative win, is Goblin Charbelcher

Here's a sample decklist (NOT OPTIMISED):

Land: 16

8 Mountain
4 Scalding Tarn
4 Bloodstained Mire

Draw: 8

4 Burning Inquiry
4 Goblin Lore

Fast Mana: 18

4 Rite of Flame
3 Pyretic Ritual
3 Desperate Ritual
4 Lion's Eye Diamond
4 Manamorphose

Combo: 14

4 Past in Flames
4 Pyromancer's Swath
4 Grapeshot
2 Goblin Charbelcher

Protection: 4

4 Pyroblast

Sideboard: 15 (rough guess, mostly meta based)

4 Tormod's Crypt
4 Red Elemental Blast
4 Ravenous Trap
3 Meta slot, most likely Blasphemous Act

I'm not sure how potent it is yet, but I suspect that it will have a goldfish of around Turn 3.

Alternative potential inclusions:

Gamble: Probably has a place here somewhere, but I'm not quite sure what to cut for it.

Burning Wish: Definitely potential for a Red Wishboard, but I'm not sure how likely it is that you'll fill it up, or what with.

Staggershock/Rift Bolt: for a more Burn-oriented list, you'd probably remove some of the actual Rituals for these.

Chrome Mox: possibly for more explosive Storming, probably in the LED slot.

Noxious Revival: for getting back Swaths discarded to the draw spells.

Thought and critiques are, as always, appreciated. However, I would prefer that this list stay mono-Red, if possible.