The Elephant Gambit
Want to surprise your opponent ? Try the Elephant Gambit - 1 e4 e5 2 Nf3 d5 - in this gambit, Black ignores the attack on his e-pawn and immediately tries to wrest the initiative from White. The main idea is that Black has sacrificed a pawn to gain a move and must obtain compensation for it. The resulting position can be sharp for White, and thus may be a good surprise opening for Black.
One of the Elephant Gambit's leading modern-day exponents is Philip Corbin:
It is generally considered unsound, because if White plays accurately Black does not get sufficient compensation for the sacrificed pawn.
🙂 Video - How to crush the Elephant Gambit (4:00 min)