weirdest thing....im talking to a few of my workmates and i was getting ready to say something and i cracked my neck at the same time and the cracking sound came outta my mouth! HAHAHAHAHA my workmates cannot stop laughing. i thought i was the only one who heard it and didnt say anything. LOL
you should walk up to them now with your mouth open and knock your knuckles on your skull. make various sounds and notes. you could even do like "shave and a haircut.. two bits!"