Written mostly for fun, although being sick is never fun.
Harry, Ron, and Hermione are three, ordinary wizards with big destinies. However, they still have to deal with the common cold.
...
For example.
"Harry. Just go to Madame Promfrey's already! You're acting silly, it has to be dusty down there." Hermione fussed.
"Unlikely." Ron muttered out of the side of his mouth. "I've seen him go under there with a dustpan, the prat."
"Shut up, Ron." Came Harry's muffled voice somewhere beneath the four poster bed.
...
"Excuse me?" The first year asked, timidly poking Harry with a shoe.
"Not worth it." He intoned, gesturing toward the makeshift shack of textbooks, parchment, and inkwells residing in the southern corner of Gryffindor tower behind Harry.
"But my Transfiguration textbook is in there and I have an essay due tomorrow!"
A violent bout of coughing came from within the shelter, and Harry cringed with sympathy.
"Alright Hermione?"
The answering grunt seemed proof enough, and Harry turned back to his crossword puzzle.
Impatient, the first year poked Harry again.
"Look mister, I really need that book!"
"I'll be honest with you." Harry confided, glancing back as if to make sure that he wouldn't be heard. "You'll probably live longer if you just go to the library."
The tiny girl looked at Ron for backup, who nodded while rubbing a rather nasty looking bruise.
...
"Where's Ron?" Hermione asked, without looking up from her book, using her scary senses.
Harry grimaced. "Sick. Up coughing all night."
Hermione considered something for a moment.
"What does Ron do that makes him feel better when he's sick?"
Harry rolled his eyes. " He digs out this old ratty magenta sweater and buries himself in it until he either dies or caves and goes to Madame Promfrey's."
Hermione frowned. "I'm rather glad I don't have to see that."
...
"What do you think Professor Dumbledore does when he's sick?" Ron asked, frowning at the man in question as he strolled down the corridor ahead of them.
"Has he ever been sick?" Harry asked, and the other two snorted.
"Probably not."
...
Albus stopped to blow his nose, wincing at the noise that thudded through his eardrums, before picking up the gossip magazine again.
"Now, where was I?"