I've had an idea!
What if there was a CD player that you can carry around and that's completely battery powered so you don't have to plug it into anything to use it? You could even use it outside!
Here's my prototype. A DIY portable CD player.
Yes, it has a CD-ROM drive from a desktop computer. I wanted to build a player like that since I was about 16. Back then CD drives still had play buttons and volume controls. But I accidentally killed it by swapping ground and 12 V. When this one fell into my hands this year, I knew what to do.