Chiptune is music at it's simplest form and is a retro nod through 8-bit emulators to the video game music of the past. While it may seem simple and small in form it's often more complex to make then other's will give credit to it. You'll see a large handful of chiptune covers in the brony community so seek it out and you shall find some great music outside of the arcade.
Check out hese artists who specialize in this style of music.
Feel free to recommend some artists not included in here (these artists specialize in it) or include up to 10 of your favorite acoustic tracks in the comments section (for an eventual best of countdown).