I stopped by Zotac's booth at Computex 2014, where the company was showing off several extremely small form factor PCs with some powerful internals inside. One of them, pictured above and called the Zbox CA320, is a passively cooled system with an AMD A6-1450 APU inside, constructed mostly out of metal that looks great.
Best of all, it's barely larger than my hand, and should be powerful enough for video playback and some light gaming. Chuck it next to your TV and use it as a reasonably powerful nano HTPC.
The other main product Zotac was showing was the recently announced Zbox Sphere OI520. Reminiscent of Google's failed Nexus Q, the Zbox Sphere is a much more powerful small form factor PC with an Intel 'Haswell' Core i5-4200U processor inside. You can also find a 500 GB hard drive and 4 GB of RAM inside, plus an LED light strip around the sphere's seam.
In fact it's very easy to take apart the Zbox Sphere. By easily twisting the top of the sphere, you can remove it to reveal compact innards with a surprising amount of space for a 2.5" drive and airflow. The system is designed for light PC tasks and multimedia, and again it looks very good without sacrificing functionality.