The Great Wall
Image by Severin Stalder, from Wikipedia
This game features one of the most unusual pawn structures I've had (as well as one of the best opponent comments!) I don't think my piece sacrifice was entirely sound, but it was certainly interesting.
The second game features an unexpected queen sacrifice--if it can even be considered a sacrifice, given the ample material White gets in return--in the Poisoned Pawn variation of the French Winawer. I admire my opponent's conception, and the resulting endgame was quite interesting.