A pawn sacrifice that is suitable for blitz but maybe not for a game in classical control.
1. e2e4  1... c7c6  2. g1f3  2... d7d5  3. b1c3  3... c8g4  4. h2h3  4... g4f3  5. d1f3  5... e7e6  6. d2d4 White has many alternatives here. 6... d5e4 