Glass Canons

Have you ever tried simple chemical experiments to have fun? But believe me, friends, it can be a double-edged sword, too!
Let me tell you about my experience, then.
We were in high school at that time. Our favourite lab was chemistry lab and we used to employ our knowledge in inventing queer chemical experiments to have fun.
One such fun was making canons.
Now, don't be shocked, friends! It's not what you think.
We would fill small glass bottles with solution of washing soda, put a few drops of lemon juice in the solution and seal them with corks. Within a few seconds the chemical reaction would take place and the cork would go 'plop!' It would travel an amazingly long distance, and those with good shooting skill would often hit a target with them!
But one day it went wrong.
I was making my little canon to play prank on a friend when the teacher suddenly appeared at the door of the classroom! I sprang up from my seat in the first row, the little glass bottle in my hand, and plop! went the cork shooting at her!
All I could do was to shut my eyes and wait for her roar...
So there ended our fun with glass canons.
Do you have any such stories of chemical fun? If yes, please share them with us!