Fan Works / Your Head A Splode

In The Cries of Haruhi Suzumiya, Haruhi asplodes Keiichi's head when she wants him to die.
Fallout: Equestria - Empty Quiver features this as the destruction of a robotic dragon, courtesy of a 40mm grenade with the explosive yield of a mini-nuke. Your Head A Splode indeed.
The Infinite Loops' MLP loops have some examples of this being Played for Laughs, including Twilight's head exploding twice after Pinkie "explains" how the Pinkie Sense works, and the Doctor's head exploding numerous times after the Mane Six loops into the Whoinverse as Daleks and decide to screw the whole extermination thing and be benevolent. The Doctor just couldn't process the concept of benevolent Daleks.
In Mass Foundations: Redemption in the Stars, The Courier finishes off the Harbinger-possessed Collector by discharging the entire clip of his M-6 Carnifex into his head, with predictable results.
In Strange Potter Harry makes Quirrell's head explode with a Reducto spell.

Calvin & Hobbes: The Series has this fate imposed on Socrates if his transmitter chip isn't removed in time. He makes it.

It happens in Hellsister Trilogy when Doctor Fate fights Superman's enemy Lord Satanis. Let's say that Fate's Order magic doesn't mix well with Satanis' Chaos-powered headgear.
Fate put his hands to his helmet, lifted it off, and, swooping low, jammed it over the red helmet of his enemy. The power of Order, imbued within the golden helm, had an immediate reaction with the powers within Satanis's headgear.
There was an explosion everyone could hear, and what happened to Lord Satanis was not at all pretty to look upon.
Kent Nelson, standing in his blue and gold uniform, hesitated a second. Then he reached out, separated his own helmet from Satanis's, and replaced it on his head. Thankfully, it contained no baleful energies. He then took Satanis’s helmet. It came away from his body, with what was left of his head inside.

The Importance of Index Cards thrusts Watch adjutant A.E. pessimal into the most difficult task of his administrative career. Who would have known indexing and filing could be a life-or-death matter in a place where heads are known to spontaneously explode...refer to 'Moving Pictures for a hint of the primal evil Pessimal encounters.

In Another Day in the Life of, exploding heads are implied to be the result of a blood seal rebounding.
In Harry Potter and the Champion's Champion, Ron makes Fleur angry enough to change into her avian form right before the First Task and she throws so many fireballs at the dragon she's supposed to be facing that its head explodes.
In Partially Kissed Hero, Harry, having recently acquired Legilimency abilities from Voldemort's memories, Mind Rapes Snape so hard, Snape's head explodes.
In Soul Scars, a troll's head explodes after Harry casts Reducto into its open mouth.
In Harry Potter & Death's Ultimatum, Crabbe Senior's head explodes when Harry casts Reducto at it.
In Trouble: When Lucius Malfoy is on trial for the Chamber of Secrets and reveals the existence of Horcruxes to the Wizengamot, his head explodes. Daphne believes that Voldemort made the spell in the event any of his major secrets were revealed.

Happens to the pirate captain in the Golden Age series. He likely didn't know that the empire planted a tooth bomb in him to keep the United Galaxies from discovering their trap.

In Ages of Shadow, this is how Jade/Yade Khan kills Maximus Domino after she's done toying with him.

The Immortal Game: This, via a blast of energy, is how Titan kills Exakktus when the latter pulls a Heel–Face Turn.
- Twilight (having recently become an alicorn herself) returns the favor during their subsequent duel. By punching him in the face. Being a Physical God, this barely slows him down.

Pokémon: Attack of Mewtwo's first chapter has Mewtwo, or rather, Mewthree, tell Sarah to shut up, or he'll do this to her. Sarah continues to defy him, and so he uses 'sichic' to do so. Sarah somehow survives this.
In Poké Wars, this is the fate of Misty's Psyduck when he's undampened (aka, having his Power Limiters removed), the extreme overload of psychic power being too much for him.

From Bajor to the Black, Part II has Eleya take out a Borg drone who's adapted to her phaser rifle by ramming said rifle through its Deflector Shield and into its mouth and then pulling the trigger.
Frostbite has a couple of instances of Frickin' Laser Beams making Breen mooks' heads explode. One such line:
"The disruptor bucked in [Tess's] hand as she fired and her target’s head exploded in a shower of sparks, bone, brains, and blood."

In KOTOR: The Prodigy of Revan, Brejik gets this treatment from Knight in Chapter VII, via shoving the barrel of his pistol into Brejik's mouth and squeezing the trigger.
"The guy didn't know when to shut up."

This funny, yet disturbing picture from a DeviantArt user that shows what would happen to Mario's Yoshi if he really did eat a live Bob-omb...

Katzenjammer: Tidearrow's head blows up after Starscream finally loses his patience with him and shoots him point-blank in the face with a null ray. The explosion is noted by the narration to be a fairly accurate representation of how Starscream's hangover feels.

Happens a lot to psykers in Age of Strife. Also how Mirande killed The Archduke.

In Ripples, this is the end result of Phobos' Beam-O-War with Allora, with him blowing her head totally off.

In Unnatural Disaster, Taylor turns all the water in Kaiser's head into steam, causing this to happen.

Your Head A Splode / Fan Works