Good openings for Blitz Games

The title says it all. What is a good opening for blitz game (5 min). I think a good opening requires the following:

• Tactical Opening
• Fast in development
• Unknown for other players

This is my opinion and I was interested, because in a tournament game I needed to play a shoot out, and I lost .

Can someone help me. I was thinking about the following openings:

• 1.b4
• 1.d4
• 1.a3

a3??

Play c4

Thanks all for this. I am thinking about the grand-prix attack and the 1.h4.

If somebody has some suggestions, please post 

I know that opening somewhere, but I don't know what it's called

The Crab.

Thank you Scottrf.

How about the Halloween Gambit:

really whatever your most familiar with and can pump out moves.

I youre familiar with theory many gambit variations such as the BDG. danish and KG are strong. I played the BDG for a while and it is very strong in blitz, where your opponent doesnt put up strongest defence and corespondence, where you put up good moves.

But for over the board find the moves to keep your position alive can feel next to impossible. 

I think most of the players don't know the Halloween Gambit opening. But 4.a3 is a safe way to prepare Nxe5!?.

But what is a good opening for black?

1.h4 does not merit accentuation such as '?!' and definitely not '?'

same is true for 1.c3

These are both very playable unorthodox openings. Why are they considered unorthodox, because you challenge the paradigm of center-control, that is traditionally viewed as sound strategy. You must be out of your mind, or very inexperienced to award 1.h4 a ?

The truth is, thread author, that asking and publicly discussing opening surprises is counter-effective, no? Because anyone who will play you can look here and see that you are preparing anything unorthodox. So basically, try anything out, and unless it follows basic principles, such as attack and hold the center, you will not find in-depth book analysis...

Why not try 1. e4 e5 2. Bc4 Nf6 and 3. Bxe7+ ? with a definite surprise !!!

This is precisely what I've been using, with some success as you can see from my trophies most of which I got from blitz tournaments. Have you been spying on me?

1. e4 h6!?