Loophole Abuse/Web Comics

In the webcomic Terror Island, one arc involving a competition to skateboard over a river ends with the alien baddie teleporting over the river instead; he wins, because "teleporting" is one of the few things not prohibited by the contest's rules, as the people drawing it up couldn't conceive of it.
A hilarious variation occurs in Schlock Mercenary, where the crew of the mercenary ship effectively avoid any litigation by becoming legally appointed bounty hunters, hunting members of the lawyer collective. They could still be sued if anyone apart from them used non-Collective attorneys, but Massey is the only non-Collective lawyer we've seen, and he's a member of the company.
- And he also killed the attorney drones, whenever any ran into him in the official capacity, being unaware of the punitive damages arrangement (Milky Way Galaxy is a big place, after all). Which is the only thing Massey was seen attacking other than with words - he stuck with the company after Collective tried some unauthorized brain surgery on him, and seem to be rather vindictive about this.

'Massey: I'll make it clearer. Your honor, please step away from the attorney drone, so that we can avoid getting any of it on you.

Therkla invokes this trope to her advantage in this page of Order of the Stick.
Webcomics trope-poking: Red Mage of 8-Bit Theater would like to direct your attention to the Air Bud clause (Ain't no rule that says you can't use dice in rock-paper-scissors). This is also Black Mage's solution to an obstacle course: Ain't no rule that you can't just blow it up!
- Also here:

Black Mage: We're going to grab the non-fabric of this anti-space time and rip it a new one.
Red Mage: Is that even possible? I'm not sure this place actually exists.
Black Mage: Then there's no rule that says we can't.

In the webcomic Brat Halla, there ain't no rule saying that a god dueling another as a tie-breaker in the Pantheon Games can't call in his independently sentient, disembodied eyeball in a Humongous Mecha to help him. For extra amusement, after t'other god tries to cite its absence in the rules, that there ain't no rule saying you can, the eyeball in its mech comes in and cites the rule in question. Linksky.
According to The Whiteboard, there is no rule forbidding the use of cross-country skis in paintball games. Doc checked very carefully.
Emily wins her first race in Misfile. Ain't no rule against driving 25 mph once you're ahead of your opponent!
Aki Alliance: There's a rule against wearing a headset to receive outside help during a Scrabble competition. Oddly enough, there's no rule against wearing a headset to give outside help to someone else during a Scrabble competition.
Subverted in this strip of Chasing the Sunset where there is a specific rule about knocking out a minotaur and stealing its keys to defeat a magic trial. They started with one rule: add a rule every time someone says "there is no rule...".
In Collar 6 Sixx plans to win her bet with Butterfly by surrendering her title to Laura and becoming her slave so that she can take part in the contest directly.
Kevin and Kell: The Domain version of the Facebook game Farmville apparently doesn't disallow players from raiding their own henhouse.
Gaia Online's four towns engaged in loophole abuse during the "Reject Olympics" plot, by recruiting nonhuman athletes for their teams.
- Johnny K. Gambino was apparently forbidden from creating new zombie serums. So for the Reject Olympics he pulled an old failed prototype from storage instead, and bummed a corpse from the Devil Imps...
In this Cyanide & Happiness strip, a character manages to get around the classic three wishes limit clause ("A wish cannot be used to grant more wishes") by wishing for more genies.
The Constitution didn't provide for insane bunny senators and therefore did not lay down a rule about what to do when one goes missing. In Prickly City, this matters.
Protoman in Bob and George does this with his Three Laws Compliance.

George: You're a robot! You're not allowed to kill humans!
Protoman: That only applies if I think he's a human, which I don't.

Tristan pulls this in Angel Moxie so she can get away with a Nonuniform Uniform in the form of striped stockings. She even recites the specific rule, noting that while there are limits on what kind of socks can be worn, stockings are allowed as an alternative and there are no such limitations for them.
Take one tabletop-gaming Rules Lawyer from our universe and drop him into an RPG Mechanics Verse with the instructions to "grant our side victory by any means possible". You now have the plot of Erfworld.
Schlock Mercenary: Presumably, after this strip there's now a company policy regarding air vents, where there wasn't one previously.
Xkcd: "There's no rule on the books saying a meerkat can't play rugby." Though, according to the Alt Text, there are rules against gorillas and golden retrievers.
Fruit Incest double-subverts this one in "Rule". There's no rule against a duck playing on the school soccer team, but there is a rule that every player on the team must be enrolled as a student. But there's no rule against a duck being enrolled as a student, either.
In Rhapsodies the local office of the Department of Minor Nuisances is unable to covertly support the Circle Band due to rules and budget concerns. Nothing wrong with doing it overtly though.
Freefall: A vital survival skill for robots and other engineered intelligences, such as the uplifted wolf Florence Ambrose. Sometimes AI and humans teach each other how to do this.