Pal's great pawn sacrifice
The Benko Gambit, invented by the great Pal Benko, is one of the more respected gambits in chess. Rather than go for a quick Kingside attack, like in the King's Gambit or the Danish Gambit, it exchanges a pawn for long-lasting pressure on the Queenside, with 2 open files. White is usually best advised to give the Pawn back, as even the best anti-Benko systems give Black a lot of counterplay and a harmonious setup even if White manages to exchange a few pieces. Here is the Benko Gambit, followed by a picture of the ideal Benko setup.