A  famous pawn sacrifice in the Flohr-Mikenas system. For the pawn White  collects the bishop pair and has the lead in the development.
1. c2c4  1... g8f6  2. b1c3  2... e7e6  3. e2e4  3... c7c5  4. e4e5  4... f6g8  5. g1f3  5... b8c6  6. d2d4  6... c5d4 