For a few weeks I've noticed that this "play him off, keyboard cat" became a big craze on the internet.
Someone on facebook posted a few videos but I didn't pay any attention to them until I saw this particular video.
The screen grab was of Spiderman... and I thought "heyyy I'll see what this is about..."
I can not imagine what I'd do if I was at this kids birthday party....
Basically, "Play him off, keyboard cat" is a compilation of random video clips containing awkward situations (that normally would not be funny) and added a light hearted keyboard playing cat at the end of each video... here's another
Here's the offical website for more: PLAYHIMOFFKEYBOARDCAT