Get a life, wake up and smell the coffee, get with the program, get a clue, get out of a rut, live to the fullest.
In reference to the piercing and deep sound of a gong in Gamelan music, q.v.
If you haven't heard it, you haven't lived.
What? You haven't heard the deep tone? Hear the gong, byatch!
You haven't drank Lapsang Souchong in your entire life?
Hear the gong, byatch!