Here is my favourite one- The Elephant Fianchetto! (Don't ask me why I named it that way-I don't even know):
I expect you to analyze this a bit further and tell me what you think.
This doesn't look that original...
With your move order, you're playing a Grunfeld as White.
But in this Morra gambit v.2, black doesn't really have any need to capture the c-pawn. He can play e5 and I don't see how white could get good play.
Nc6 is probably black's best 4th move. The Morra gambit vs is not good at all, it just gives black a lead in development, a slightly better centre, and a free pawn. Also it blocks the light squared bishop.