I was messing around with my rMBP and pressed the space bar. I didn't cause any harm but I don't know if this is normal or not. Here's a video:
YouTube: video
It's still covered under warranty. I wonder if I should bring it in or call Apple. It only happens when I press the spacebar on my desktop.
I am sure it does not. E.g. try opening Safari and pressing CMD+L followed by CMD+K. This is an invalid sequence and should also produce the sound.