I don't know the name of this one, but I've never seen it. It's strange, I know but not losing. You can get the pawn back, and you develop things. But BE CAREFUL if you're doing this because there's a tiny difference between winning and losing. Don't flame.

Comments? *dies*

...f5 is the Fred Defense to the king's pawn opening, and it is generally considered to be rather weak.

maybe post a representative game?

It is a weak gambit and should never be played...

Black sacrifices a pawn so white can get a strong attack. Not good.

I know this as the Duras Gambit, but the posts above me are correct... black sacrifices a pawn for absolutely no compensation. In fact, it's WHITE that gets the positional bonus.

this open's up both of white's bishop, and queen. While blocking in you bishop and knights. Gambit's are usually meant to be offensive, but this is very defensive and sucky. 

Why 5. fxe6?

5. dxe6 and black is screwed.

When I read that, I saw "Dumas Gambit" and thought it fitting.