This app was mentioned in 5 comments, with an average of 1.20 upvotes
My wife and I play Sea Battle over Bluetooth (basically Battleship). Good fun!
Another good mention is Ready Steady Bang. It doesn't necessarily use two tablets, but still a fun, local, multiplayer game that you can play in a tournament style if you have lots of people.
Hmm... I imagine putting it in tent mode, playing something like: https://play.google.com/store/apps/details?id=com.byril.seabattle