I love karaoke, its my favorite hobby, the primary difference between Karaoke and sing-along songs is the absence of the lead vocalist
I've never tried Karaoke. Is it fun?
Yes its really great! You can also try a game on PlayStation 3, Nintendo GameCube, Wii, Xbox, and Xbox 360 called Karaoke Revolution 
I don't own any of those, but isn't half the fun of karaoke embarrassing your self in public?
Yes thats the thing about it :D you have to drink a bit before! also karaoke can refer to an instrumental version of a recording
Oh, it can?
Yes, but first try the game alone :D about 632 songs are in the game  karaoke revolution, so you can practice at home :D