You sign up for a song and then when it's your turn to sing, the microphone cord can be slid down this guided-track type thingy to make sure it can reach any seat! It was incredible!
And the best part? You're on a bus and you have a CAPTIVE AUDIENCE! When you sing karaoke at a bar, you have to weigh what you want to sing against what the crowd is likely to tolerate. If you pick a horrible song, everyone will simply go outside and smoke until your song is over. But on a bus, there's no escape. So if you want to sing Believe by Cher (Yes Sean, I'm looking in your direction) there's nothing anybody can do but listen. Hahah.