Pawn Sacrifices - Part I

When you sacrifice a pawn, you do so for a couple of reasons. One is to gain the initiative ie while your opponent is taking your pawn, you are making threats elsewhere. Another is to free up a square or open lines for your pieces.
In the following game (played this evening at my local chess club) I decided to make a dynamic pawn sacrifice that met all the conditions. In giving up my e pawn I freed the e5 square for my knight, opened the d file for my rook, and threatened to wreck my opponents king side pawn structure. It also had the effect of throwing my opponent on to the defensive, and allowed me the reach clearly winning position. Unfortunately I reached this position with 20 seconds left on my clock, and unable to see a clear cut win (although it was always there) I took a draw by perpetual.

Russell,L - Press,S [C55]
ANU Winter Rapid Canberra, 25.06.2008

1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.d3 Be7 5.c3 0-0 6.0-0 d5 7.exd5 Nxd5 8.Re1 Bf6 9.Nbd2 Bg4 10.h3 Bh5 11.Ne4 Re8 12.Nxf6+ Nxf6 13.Bg5 h6 14.Bh4 (D)
14. ... e4 15.Bxf6 Qxf6 16.dxe4 Ne5 17.Be2 Rad8 18.Qb3 Nxf3+ 19.Bxf3 Bxf3 20.gxf3 Qxf3 21.Re3 Qf4 22.Qxb7 Rd2 23.Rf1 Rxf2 24.Rxf2 Qxe3 25.Qb3 Re6 26.Qb8+ Kh7 27.Qb5 Rg6+ 28.Kf1 Qc1+ 29.Ke2 Qc2+ 30.Ke3 Qc1+ [ 30...Rg3+ 31.Rf3 Qc1+ lead to a win] 31.Ke2 Qc2+ 32.Ke3 Qc1+ ½-½