There are situation when you know something is going off from or to your computer and you have no idea what that is or who's doing that. On the other hand, sometimes you are just curious to know (I know I am) what's cooking.
Scrip below is analyzing every connection that your machine have. Either TCP or UDP. It'll give you port numbers, IP addresses, names of the processes issuing connections, their PIDs, locations on HD, user names, connection statuses, and hints on protocols for used ports