Harry knew he shouldn't have done it, but the temptation was there.
He and Hermione were in the Room of Requirement hiding out from Ron Weasley and Lavender Brown, the latest Hogwarts couple to have formed when he saw them...
The cage of Cornish Pixies that he had seen in his Second Year when Lockhart had been the Defence Against the Dark Arts Professor.
In hindsight, he should have taken heed of the warnings that Luna Lovegood had given the two youngest Weasleys had talked about Pigmy Puffs, that if a Cornish Pixie ate one, it would have had the effect of making them drunk.
Obviously, Harry was a bit drunk himself, and Hermione wasn't far behind him when the idea came up. And with Hermione, a bit drunk herself, the logical side of hers rejected the opportunity to play, and instead, the Firewhiskey influenced side had free reign.
Having waited until the party that was going on had calmed down, Harry gave the signal to Hermione to take some of the Cornish Pixies in one cage up to the girl's dorms, whilst Harry did the same on the boy's side.
As soon as a fully clothed Harry let his head hit the pillow, he was out for the count, not aware of the chaos being unleashed.
Eventually, morning came, and Harry found himself waking up in a bed that had been turned apart, his trunk upside down, and Neville hanging off the light surround, with a Cornish Pixie laying drunkenly on the door frame.
Getting up, he remembered how he and Hermione had been drinking in the Room of Requirement. Heading down the stairs, he could see Professor McGonagall and Madam Pince casting spells to try and get what looked like drunken Cornish Pixies into a cage.
It was then that he remembered what happened.
"Whoops..." he said trying hard not to drop Hermione in it as well. "...I plead insanity."
Being in detention with Hermione for the rest of the year and the 1000 Point deduction was well worth it though!