"Let's have a picnic," suggested Harry brightly one summer's afternoon. He, Ron and Hermoine were sitting in a favourite musty corner of Hogwart's vast library.
Ron looked sceptical. "But we'd have to make sandwiches, and..." he hesitated, then weakly finished "...jam?"
"No, stupid, I mean a magic picnic of course," snapped Harry.
"I don't think you should be using magic to make a picnic, Harry," warned Hermoine without looking up from the immense tome she was perusing.
"Alright, well don't come then," shot back Harry. He rose and strode out of the library. Ron and Hermoine exchanged a despairing look, then followed his receding form up to his room.
Harry reached under the bed and pulled out an empty wicker basket that had contained Ron's last food shipment from home (he'd won it in a bet). He set it on the bed, drawing out his wand as the others burst in, Ron breathing hard from the exertion of their journey.
"Harry," began Hermoine, "I really don't think you-"
"Oh shut up, Hermoine. Delicious Picnicus!" With these words he flourished his wand in the general direction of the basket.
Nothing happened.
"I'm not sure Delicious Picnicus is a spell, Harry," reproached Hermoine. "You should really read some more books."
"Books, shmooks," said Harry. "I must have just waved the wand wrong." He began to lift the basket, but stopped when he felt its weight. "Hullo," he exclaimed, "I think it worked!"
He opened the basket, and sure enough it was filled with delicious looking sandwiches and cakes.
"Wow, nice one Harry," said Ron, "that lot looks smashing!"
Harry grabbed the blanket from the bed and turned to Hermoine with a self-satisfied grin. "Looks like you're the one who should be reading more books, Hermoine. Now me and Ron are going for a picnic, and we don't want you to come."
Ron blushed, and began to object. "I don't mind -"
"Shut up, Ron. Grab the basket and lets go."