You walk down the corridor, feeling Harry Potter's wand in your hand. It fits perfectly, as if it were made for you. Which, technically, it was.
You wonder what spells you should try out. You think back to the first book - there's alohamora, wingardium leviosa, lumos...
You start to think of more. Accio, serpensortia, petrificus totalus, expecto patronum... spells whirl around your head.
You take out your wand, wondering what spell to cast first.
You point at a painting.
Still nothing. You walk further along the corridor, feeling very stupid indeed. You pass paintings, suits of armour and little pottery bits.
You whirl round.
This time it works. The spell streaks across the corridor and hits - a teacher.
Your mouth falls open as tiny Professor Flitwick flies vertically into the air. You try to break off the spell, but the more you wave you wand around, the more Professor Flitwick flies wildly around in the air. He gives little whoops of surprise as he hits the walls and ceiling.
Finally you decide to just drop your wand. Professor Flitwick comes flying down and hits the florr. He falls asleep.
The commotion brings teachers and students into the corridor. You realise what this looks like - you're standing in front of a teacher who has passed out, and your wand is lying barely three inches away.
Later that day, you are given a detention, and made to polish hundreds of medals without magic. That night you go to bed, and wake up back in your own bedroom. The adventure is over.