In a scene where there is no real high stakes action or scenario that would require a gun, a character randomly draws one. Bonus points if they actually use it.

(It's Always Sunny in Philadelphia) During a news interview, Frank Reynolds decides to re-enact his story of how he scared away two people who tried to mug him. By proceeding to whip out two pistols and mimicking gun sounds

(Wreck-It Ralph) This one gets me the most tbh, it was so unexpected. After almost drowning in \[nes\]quicksand, Sergeant Calhoun rescues herself and Fix-It Felix by punching the piss out of Felix repeatedly, causing sentient Laffy Taffy to lower themselves down and help pull them out. Afterward, Felix and Calhoun exchange longing glances, causing the Laffy Taffy to serenade them. Calhoun gets annoyed and draws her pistol, firing it into the sky to scare them off. Up to this point, the only guns that had been used in this movie were PG-13 pew pew rifles, so her pulling out a Deagle was all the funnier. 

(South Park) The one this post is named after of course. In the episode, R. Kelly spends time doing a mockup of his irl series "Trapped in the Closet." Multiple times, in response to very low stakes things, he says "Now I'm starting to get angry... (and/so) I PULL OUT MY GUN!" and starts waving it around while continuing to sing. 

(Loved Trope) I PULL OUT MY GUN