Some jokes in the comic have been used multiple times; here is a list of them in chronological order from their first appearance.
Many of the following, while they may have appeared as a gag, are more of a recurring element.
Vaarsuvius's Gender Edit
Vaarsuvius is ambiguously gendered. Their gender is unclear in each of their appearances. According to The Giant, this was originally unintentional (he had thought of Vaarsuvius as having a specific gender), but when readers couldn't figure out Vaarsuvius' gender, he decided to go along with it.
Vaarsuvius always forgets about their (see above) raven familiar, Blackwing.
This was parodied in Comic 674, where none of The Order recognized Blackwing, despite having seen him before (Haley even named him! However she later stated that she was "busting V's chops" in 943). From this comic onward, Blackwing became a more important character, always perched on Vaarsuvius' shoulder.
Up/Down a LevelEdit
Thor gets the odd mention in The Order of the Stick, often appearing in cutaway panels for a gag.
The Lawyers Edit
Jones and Rodriguez always appear for a legal scene of any sort.
The tentacled creatures are continuely landed on by characters in Order of the Stick.
Haley mentions the Flumphs as an "easy recurring joke" in 680.
Banjo the Clown Edit
Explosive Runes Edit
V's infamous spell is possibly the best known gag of all.
Belkar mentions to have been a victim of it 11 times in a day in 323.
"Gate? What Gate?" Edit
The MitD's famous quote, also proof he is ignorant of the gates' existence, for some reason.
In 2011, an OOTS Christmas ornament displayed Roy and Xykon battling it out, with a caption that says, "He made his list, checked it twice, and had no idea who the guy with the sword is."
"Isn't Your Dad Dead?" Edit
Whenever Roy mentions the manifestation of his father, one of the Order of the Stick says "Isn't your dad dead?". this is said variously by Elan, Belkar, and Haley (even when she lost her voice).
Belkar has killed each of his kobold counterparts in the Linear Guild and turned their head into "something wacky". He also intends to do this to the Oracle, but is thwarted by the Oracle's preparations for his own forseen death.
Belkar turns Yokyok's skull into a tortilla chip bowl in #358, as well as using his tail and other parts to make extra chunky salsa (though he later states that had no intention of actually eating the salsa).
Thor's Might Edit
Durkon's massive power-up spell.
Durkon's Fear of Trees Edit
Belkar's lead sheet Edit
The sheet Belkar carries to 'prove his manhood.', although he actually uses it to block Miko Miyazaki's Detect Evil. He has left it behind at Azure City as of 779. He references the gag when confronted with the lead sheeting around Girard's Gate.
Sexy Shoeless God of War Edit
In 476, Belkar proclaims himself a sexy shoeless god of cooking.
"Dunh dunh DUNH!" Edit
Elan says dunh dunh DUNH! To heighten dramatic tension, as if there were a soundtrack to his life. Even Roy and Tarquin has picked up on the gag.
Roy mentions the gag in 490.
Nale refuses to do it and is chastised by Tarquin for it in 821.
Bardic Nudity Edit
Elan believes by being naked, he'd have a lower Armor Check penalty.
"Belkar's Right." Edit
After Durkon was turned into a vampire, Roy begins to admit that Belkar is right about some things. Belkar is always weirded out by Roy's agreement with him.