At the end of the It's Always Sunny in Philadelphia episode "Paddy's Pub: Home of the Original Kitten Mittens" (S05E08) the gang shows their merchandising video to a bunch of possible investors. But due to time problems they weren't able to properly cut it and thus the video suddenly ends with a totally unrelated scene showing Frank spray a woman, probably Sweet Dee, with a fire-extinguisher with a burning house in the background.
I wonder if this scene is referencing a specific episode, but right now I can't get my head around which one that would be. Or is this just a random scene supposed to hint at some other non-documented adventure of the gang? (And is this actually supposed to be Paddy's Pub in the background?)