You'd need a pretty steady connection to pull something like this off, but it is still pretty cool.
One of the PS4's niftiest features is the ability to "remote play" in conjunction with the PS Vita. It essentially works the same as the Wii U's off-screen play, where you can stream your PS4's gameplay to your Vita whenever you need to go to the John or your mum/wife wants to use the TV. While the intent is for the feature to be used within your own home, with LTE bringing blazing-fast wireless speeds to mobile devices, one man has decided to put remote play to the test.
In the video above, he is able to play his PS4 games at 30 FPS without too much noticeable latency, despite being over 10 miles away from his home. In theory, he could be halfway across the country and still be able to produce the same results (provided he was still able to get a stable LTE connection).
Keep in mind that this is something you probably shouldn't be doing unless you have some kind of unlimited plan for your cellphone, as using remote play eats up quite a substantial amount of data (as you can imagine).
The PS Vita's remote play feature works with all PS4 games, and a selection of PS3 games, and is available to everyone right now (provided you update your Vita to the latest firmware).