the greek gift
This is also known as Classic Bishop Sacrifice,with 10.Qg4 white would lose his big advantage 10...f5 11.Qg3 12.Bxf4 Nf5 but white is winning anyway. a better move would be 10.h4 f5 11.h5+ Kh6 12. Nxe6+. note that 11...Kh5 is considered as an inferior move allowing a mate in 2.a better move for black is f4.
well anyways you can look more about this classic sacrifice
http://en.wikipedia.org/wiki/Greek_gift_sacrifice