Comment by dylukes

What do you think is running on your favorite game consoles (that aren't Xbox)? I'll give you a hint, it isn't Linux.

Nintendo is using a custom OS but with a huge chunk of user space borrowed from FreeBSD. Sony on the other hand just went and forked FreeBSD outright.

You might also want to look into what OS are being used for server environments. A lot more BSD there than you might have initially guessed.