VirtualBox

VirtualBox is like a magical computer that can go inside your computer, just like how a dollhouse can go inside your house. Once it goes inside, you can create another pretend computer or more (you can create as many as you want) inside the magical computer. This pretend computer can do whatever you want just like your computer, but it doesn't actually exist outside the magical computer.

This pretend computer can even have a different operating system like Windows or Linux, which means it can look and feel differently from your real computer. When you're done playing or using the pretend computer, you can put it away back into the magical computer, and it won't take up any space in your real computer.

And because it's a pretend computer, you can do things like test programs or play games that might not work on your real computer without worrying about breaking anything. VirtualBox is like a really cool toy box for grown-ups who like computers!