Latvian gambit probably.
Most Violent Black Opening

How about the Portuguese Variation of the Scandanavian?
The line runs: e4 d5 exd5 nf6 d4 bg4.
This line is quite forced, the only alternative to d4 really is
1) c4 which runs into the gambit c6 dxc6 nxc6 nf3 e5 d3 bc5 which gives black good compensation for the pawn.
The main line of the Portugese runs: e4 d5 exd5 nf6 d4 bg4 f3 bf5 bb5+ nbd7 c4 e6 dxe6 Bxe6 c5 c6. However, many players have fallen for the little "trap" where instead of Bb5+ white plays c4 where black replyes e6 dxe6 nc6! be3 bb4+ nc3 and qe7 where black has excellent play for the sacrificed pawn(s).
Although the Scandanavian doesn't look extremely aggressive, playing nf6 on move two going into the Portugese Variation usually gives very entertaining and fighting games.

Latvian scores well i believe when plyers do not have the book in front of them and you have already digested it...I play the Latvian very frequently against players ranging from 1300 to 2000 and ive had many close ones but i have yet to lose...sidenote you MUST have the tactical stomach for this opening i believe

where can i find the main lines for the latvian? Please help
thx, jim
Start here:
http://www.chessville.com/UCO/index.htm
There's tons on the Latvian spread throughout the site. If that's not what you're looking for, wikipedia should have the mainline:
http://en.wikipedia.org/wiki/Latvian_Gambit

Saint George 1.e4 1.b5
I thought the Saint George was 1.e4 a6???
http://en.wikipedia.org/wiki/St._George_Defence
The Latvian is very explosive for Black, but it generally explodes Black's game instead of White's!
Most responses to 1.e4 can lead to dynamic and aggressive openings, even if they don't seem like it right away. (e.g. 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6. The Ruy Lopez has many aggressive lines in it.)The Guioco Piano, in particular, or the Four Knight's game have many gambits and attacks against f7 or f2 in them.
Try out some solid defenses that also have attacking chances to boot; like the French Defence or Nimowitsch Defence. (Nimzo: 1.e4 Nc6.)

Hmmm... I've never tried the Nimzo Defense... I'll try this as well. And yes, after playing the Latvian a few times, the explosion that occured was NOT in my favor.

The 1. ...d4 response fits what you're asking for, but without sticking in my own 2 cents about your desire for fireworks so early on, let me ask if you know Alekhine's Defense. Something tells me it may fit your style. Check out the first paragraph of Wikipedia's comments on it, and then explore some games right here on this site. (Use the Game Explorer).
http://en.wikipedia.org/wiki/Alekhine%27s_Defence
Hope you like it!

mm.. I know another one that may be called one of the most agressive variations. It does require some cooperation from white to be achieved on the board though.
The Traxler Counterattack
Maybe I should rephrase the title as "aggressive," but I'm just wondering what the most firework-ish defense or counter-attack with the black pieces against 1.e4 is in general OUTSIDE OF THE SICILIAN (since I know most will pick this). This is an opinion question, I know, but I was just wondering what the members of chess.com found to be the most vicious play...