I quite like making Open Source Software projects. (Open Source means that anyone can look at, suggest changes to, or use the code). Usually, nobody uses them, however they're still useful and fun to make.  For example, I made MCPing, the source for which you can find at randomairborne/mcping. It's a simple tool to test Minecraft servers, however I don't believe anyone else is hosting it. It's not designed for that.  I have, however, made a project I do want people to use. KeyValueSystems/SimpleShortener is an easy-to-use link shortener designed for anyone to be able to use.