Potterhead - Gryffindor

"Hogwarts, Hogwarts, Hoggy Warty Hogwarts,
Teach us something please, 
Whether we be old and bald
Or young with scabby knees,
Our heads could do with filling
With some interesting stuff,
For now they're bare and full of air,
Dead flies and bits of fluff,
So teach us things worth knowing,
Bring back what we've forgot,
Just do your best, we'll do the rest,
And learn until our brains all rot."