Hermione Granger kicked Albus Dumbledore in the nuts.
The unflattering event occurred during her sixth year at Hogwarts. At a certain point prior to the Headmaster's unfortunate passing, Miss Granger became suspicious that her schoolmate Harry Potter was secretly collaborating with Dumbledore and resolved to confront the Headmaster directly. In an uncharacteristic display of openness, Albus admitted to this much and more, going so far as to inform Miss Granger that he had been, reluctantly, engineering Harry as a trap/bait to rid the world of Voldemort. Also coming under discussion were certain actions (or in some cases, inactions) concerning the tragic death of Dumbledore's sister, his alliance with Severus Snape, and what some might perceive to be a longstanding habit of maneuvering others to handle issues which he himself did not wish to directly confront.
After hearing him out, Hermione considered the matter for a few moments and is reputed to have concluded that, regardless of how others might judge him, from a logical perspective nearly everything Dumbledore did could be excused. At least, when considering the enormity of the threats involved and his unwillingness to risk becoming an all-powerful overlord who decided things for the world based solely on his own extraordinary affinity for magic.
Miss Granger then stood up and stated, "But this is for Ariana!" before connecting her foot with his nether regions in what a witness who happened to be flying by termed 'the most brilliant display of World Cup football this commentator has ever seen.'
It has been independently confirmed that at the precise moment of impact, every single Chocolate Frog Card in the world with Dumbledore's image on it froze in an expression of pinch-faced pucker-lipped distress 'like he was sucking on a lemon', to the confusion of their owners. They remain so to this day, and efforts to install a post-mortem magic portrait of the man himself in the Hogwarts Headmaster's office have yielded identical results.
The exact nature of this phenomenon remains a topic of scholarly discussion.