Go on stage, off your head on crack, and sing the drugs dont work, fall off the stage face down in to a pile of vom
It's not about the vocal performance but more to show you can have fun with your colleagues and have a laugh at your own expense.
This.
is this something you have to attend?
Ive never heard of a company taking people out to karaoke :/
You need to have a good set of pipes to pull this off though, theres some difficult notes in there.