The 4th
Obligatory (crap) Fourth of July firework picture… It really is harder to take these than it looks: 
Just rememember, dry ice and water should not be enclosed in a small, sealed container… unless you want the container to explode… in which case remember the DIY Explosive Makers motto “too much is never enough” (if that’s too hard to remember, you can substitute the “use it all” formula is most cases).