Borkware's First-Timer's Guide To WWDC:

"The labs where you can chat with Apple engineers are an invaluable resources. It is a scarce, shared resource, so treat it like you would computationally: pretend to be a mutex. You walk into the lab you want and shout "I AM ATTEMPTING TO OBTAIN A LOCK ON THE MEDIA PLAYER FRAMEWORK ENGINEERS". If an engineer is free, you'll hear "LOCK SUCCEDED" from the back, and you can go to the engineer who just shouted and ask your questions."

See ya there.