This one is a tie between three consecutive episodes that cover most of the third day of the Grand Magic Games.
First is episode 167. This is just a badass episode. Erza kicks 100 monsters' asses and Cana uses the always amazing Fairy Glitter spell. This is the start of Fairy Tail's comeback.
So episode 168 is fight for top spot because of three reasons: 1. millianna kicks ass (girl power) 2.We get to see more of Rufus's amazing maker magic 3.An awkward moment for Eve
Episode 169 is another favorite of mine because of the two epic face offs: 1. Laxus Dreyar vs. Team Raven Tail 2.Wendy Marvel vs. Sherria Blendy