I once made this for testing some Libgdx stuff, now I improved this project a bit and published it.
Basically it’s just a “simple” pong clone.
You can play local on a keyboard against your friend or online.
Everything else is self-explanatory… 
http://fs2.directupload.net/images/150621/temp/m9r2vz4s.png
http://fs1.directupload.net/images/150621/temp/qqp8txb5.png
I made a gamejolt article for this game here: http://gamejolt.com/games/arcade/particle-pong/50618/.