Ideas for Weasleys' Wizarding Wheezies?

[kizor0]

Hi. After getting positive feedback in chat, I decided to have a
little fun and ask people: Were you in the position to come up with
some enchanted novelty items, what'd you give to the wizarding
community? Don't be too concerned about feasibility - we have very
little idea of what is and isn't doable anyway.

I know it'd be both good form and good for the topic if I provided
some initial examples, but I'm afraid that I'm rather tired right now
and consequently my imagination is stuck in loose cannon mode. If I
tried to come up with something the result would be about as sane as
candy that makes the eater change gender for a few seconds. And now
I'll be off, as there's a good chance I actually typed that last
sentence out loud, which in turn means that I really should go to bed.

- Kizor