In the first book, Patty gets angry at Greg during a school play and basically throws a temper tantrum. Greg gets annoyed and thows an apple at her. Just so you know, the play was of Wizard of Oz, with Patty as Dorthy and Greg as a tree and the apple. Wasn't seen as awesome in Greg's mothers eyes.
Also doubles as heartwarming: after the play, Greg goes out to see his family, and they just walk away disappointed...except Frank. Frank looks down at Greg, and then...
Frank: I thought she deserved it.
In the first movie, Rowley tries to invoke this trope by restraining Rodrick from attacking Greg, doesn't really work.
Another one from the movie, on Halloween, Greg and Rowley manage to intimadate the teenage bullies with a weedhacker.
Pretty much the whole Exploded Diaper scene in the second movie. Although In-Universe, everyone was cheering for Mrs. Heffley dancing in the background. Also during that scene Rodrick gets back at Bill for being a jerk to him by kicking him out of the band.
Fregley gets one with that scary story he told in the third movie.