1) The files casablanca110.desktop etc are
Visual Studio Solution files
. They provide a structure to organize projects in Visual Studio. You can build this solution to obtain the executables for the samples (BingRequest, BlackJack, SearchFile etc).
2) The source code you are seeing could be from the master or development branch on CodePlex. We continuously push changes to the development branch. Hence, the version you downloaded could be slightly older.
To run the BlackJack sample, build the casablanca<vsversion>.desktop solution. From the binaries drop, you will have to start the Blackjack_Server first and then start the BlackJack_Client. BlackJack_UIClient is WinRT only, hence it will not be present
in desktop solutions. BlackJack_Client is a command line client which will work on desktop.
I would suggest starting with some of the simpler console application samples like BingRequest and SearchFile and then moving on to the BlackJack one.