Almost 2 years ago now, I built myself an Arcade (or fight) stick. It runs on XBox 360, PS3, or my PC. This type of stick is mostly used for fighting games, but I like it for anything that doesn't need an analog stick. I built it as part of a plan to eventually make my own arcade machine, something that I haven't yet gotten around to, but still plan to do.
I've started planning to make a new one. The big difference is this time, I'm going to put an MK808 inside. It's an Android based mini-PC. They're running about $40 on Amazon, and perform fairly well for android gaming. I'm going to use this along with RetroArch to have an all in one retro gaming machine.
I'll have a USB port on the back as well for either a keyboard/mouse when it's needed or to plug in an additional controller. Since I don't actually have the space in my house for a full arcade machine, this will be the next best thing. Who knows, maybe eventually I'll stick a monitor on it, and build a box around it.