In the finale of Superman: The Animated Series, Superman is brainwashed by Darkseid to attack the Earth. By the time his true memories are restored, he is a pariah and Supergirl is in critical condition. Superman decides to "settle it" by going to Apokolips - taking down Parademons, Granny Goodness, the Furies, and Kalibak before facing Darkseid himself.
In an alternate universe where Lex Luthor is elected president and kills the Flash, Superman breaks into the White House and fries Luthor with his heat vision. Then the Justice League takes over the world over this.
When Archer found out that the Irish mob had been selling people fake cancer medication, he went on what he described as a "Chemo-fuelled rampage" straight out of Man on Fire (with a side order of Magnum, P.I.). Oh, and filmed the whole thing, and called the result "Terms of Enrampagement," or possibly "Casablumpkin."
It bears repeating that he was actually on chemo at the time. Also, he shouts "RAMPAGE!!!" before attacking.
Then, of course, there's Wodehouse's example in WWI after the pilot he tended to was shot down. That one needs to be seen to be believed.
In a What If? episode, we see just what Commander Gordon will do if Barbara is killed in the line of bat-duty.
In the episode "The Clock King", Temple Fugate makes a Stoic Rampage of Revenge against Mayor Hill.
When EricCartman decides to give Kyle his AIDS, Kyle does this claiming he is going to break everything he owns in a charge to Cartman's bedroom.
Arcee in Transformers Prime has a moment where she stormed the Decepticon ship, killing Vehicons to find an amnesic Optimus.
Optimus goes to fight Megatron in a one-to-one death match after the latter nearly killed Raf.
Predaking proceeds to hand Ultra Magnus and Wheeljack their skidplates after they blow up the Predacon clones.
He does it again to the 'Cons when he finds out they were behind the destruction of his brethren, culminating in beating the slag out of Megatron.
This is how Morph from the 90's X-Men cartoon begins the second season, after being corrupted / brainwashed into hating his former team for, as far as he's concerned, abandoning him to die. In the course of ONE EPISODE he 1) invalidates Cyclops and Jeans wedding and sends them into a trap on their would-be honeymoon, 2) sends Professor X and Magneto into another trap in Antarctica (where they will remain stuck for the entire season!), 3) tricks Gambit into kissing Rogue, knocking him out for hours and saddling Rogue with an uncontrollable version of his powers, 3) pisses off Jubilee then tricks her into going to the headquarters of the "Friends of Humanity" (an anti-mutant terrorist group) and reveling herself as a mutant, 4) locks Beast in the "Danger Room" alone with the difficulty settings set dangerously (almost fatally) high, and 5) tricks Rogue and Storm into going to try and stop a riot with no back-up, then makes the police think THEY were the instigators and has them open fire on Storm, putting her in the hospital. Literally, the only X-Man that escapes his rage is Wolverine. YMMV on whether this is just because he hadn't gotten to him yet when he was exposed or for some other reason (and if, so just what the reason couldbe).
Wolverine would've been much harder to fool: one sniff and Wolverine would've known it was Morph.
Family Guy: When Quagmire finds out that Brian he slept with his transsexual father.
WHERE IS HE?!WHERE IS THAT SELF-CENTERED, ARROGANT SON OF A BITCH?!
The Avengers: Earth's Mightiest Heroes: After Amora the Enchantress nearly becomes a slave of Baron Zemo, leader of the Masters of Evil, she tortures each member one by one, building up to an attempted killing of Zemo.
The "Putting Your Hoof Down" episode involves Fluttershy colliding with the jerkass ponies she came across after she gets her assertiveness from Iron Will.
In Twilight's Kingdom Part 2, once Tirek blows up the library, Twilight stops trying to hold her magic back and instead goes all out in trying to stop him.
American Dad!: Hayley flies into one of these every time she gets dumped, leaving a trail of collateral damage in her wake. Apparently, this had been going on since childhood, where she once set the classroom on fire and killed the pet hamster.