Hedgewars is a strategy turn-based artillery game for the Mac. It is available for the Mac, Windows and iOS. It is free for Windows and Mac, and you can even download and compile the source code yourself if you want to. It is $0.99 for iOS. If you have played any of the Worms games in the past, you will invariably feel right at home with Hedgewars. It is a very good clone of it. The mechanics are very similar and so is the gameplay.
There are a few different game modes that you can play. There are both local and online modes. The local modes let you battle with a computer opponent or play with a friend on the same computer taking turns. If that turns out to be too boring, you can play over the Internet against other human players.
I like the training missions, which let you test specific weapons in mini maps. Those are great for perfecting your aim or learning what a specific weapon does in the battlefield.
The game features huge maps which look great. The characters all have funny costumes and the voice acting is very funny.
In short, this is a nice game to kill the time. It is fun, and matches usually only last 10 minutes or so.