A unit of measure where the descriptive term is never the same value and always unknown.
1 = x:y:z
Where x = any number of minutes, y = any number of seconds, z = and number of milliseconds
A: Dude, this Olsen video I'm downloading is gonna be sweet!
B: Awesome man, how long has it got?
A: Ahhh it says 3 minutes to go...
B: Oh man, they're Microsoft Minutes; you'll be there for another hour at least!