Nickelodeon (or Nick for short) is the channel that plays SpongeBob SquarePants. It is very successful to kids who have nothing better to do.
Nick started off as a channel called "Thing That Has An Aluminum Propellor Attached To A Stick Oh Yeah And The Propellor Spins". Sadly, that name was shortened to Pinwheel, an uninteresting, not-catchy name.
Yeah, everyone hated Pinwheel. So it was changed to Nickelodeon, and all was forgiven.