The hyoid bone is unique in the body in that it does not directly articulate with any other bone but rather is held in place by ligaments and serves as an attachment for muscles.
The thyroglossal tract goes right through the middle of the hyoid bone; if a thyroglossal duct persists in an adult and forms a cyst, the middle of the hyoid bone may need to be removed.
Muscles attached to the hyoid bone:
I have been told that one of the most painful things you can do to a potential attacker is to break their hyoid bone. You do this by doing a choke hold just below their mandible and squeezing HARD. I have never yet had reason to attempt this and hope I never have to. If you have to resort to this, make sure you are ready to plead self defense - there is a decent chance of ... erm ... accidentally ... killing the assailant.