Now you, too, can have your own cryptocurrency! Thanks to Matt Corallo, a veteran bitcoin developer, you can easily create your own at this site: 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 for the grand sum of as little as 0.05 Bitcoin, you can have your own cryptocurrency in 30 minutes! Source code and some customizations are a bit extra.
Once you have your own "coin", you just need to convince people that it is worth something.