mspohr writes "Since the code for Bitcoin is open source, we have seen the creation of various Bitcoin clones and enhancements (Litecoin, Dogecoin or Coinye West, anyone?...
There are about 70 listed on this site.) This article explains the process of making your own. Thanks to Matt Corallo, a veteran Bitcoin developer, you can easily create your own at coingen.io.
He has automated the process of modifying the source code to create custom currencies. Just enter in the name for your new currency, a logo image and set a few parameters (or accept the defaults), and you can have your own cryptocurrency.
Source code and some customizations cost a bit extra. Once you have your own 'coin,' you just need to convince people that it is worth something."