Karaoke is awesome!  Have you ever tried it?
I am too shy to sing but I like to watch it. It's been popular for a long itme, which I didn't know. Since the 60s at least
It was a brilliant idea coming up with it!  Do you know where it first started?
Well, sing-alongs have always been popular, but I am not sure where Karaoke as we know it was developed. 
The Karaoke machine is pretty cool!  Who invented it?
Not sure. But Karaoke has another usage, which is to refer to the instrumental version of a recording (i..e., no vocal track)