Ticket to Ride Pocket is free (again)
Sorry, don't have the itunes link handy. Great async boardgame that I find fun playing against the CPU as well. Wait, maybe its not async but real-time. Despite it being a boardgame adaption, it plays surprisingly well on an iphone. If you want to play on your ipad, look for the version (or Ticket to Ride Europe) that doesn't have pocket in its name. Those aren't free though .