Here is a game from the 71st Corus Tournament, GM Iturrizaga - GM Leon Hoyos with full annotations and commentary:
This is a great game to show how to properly defend against a speculative sacrifice. You must not lose your nerves and try to think logically and problem solve through the trouble that the opponent poses to your position. In this game the sacrifice was made for attacking chances against the King. However, white was able to slowly push black back and then actually gain the upper hand and take over the attacking chances.