Diablo III has a fun couch co-op experience. The sports games are really fun, and have a lot of replay for two players.
There are also a lot of indie/downloadable games that are great for kids.
Resogun is my favorite game on the system so far. I got Resogun free via a friend's ps+ account. So far I've bought Destiny, Wolfenstein New Order, Last of Us Remastered, Dragon Ball Xenoverse, and Blood Born. And honestly, if I was not given the system and had gotten really good deals on those games, I could easily live without the ps4 right now. Not a bad system, but nothing to write home about. there are about 100x good games for all the systems that cam out before this generation so far, nothing sells me on this generation yet.