This interactive circuit simulator with a breadboard style user interface was created as my A-level Computing project. It is built using a C#+WPF GUI frontend and a C++ backend. Visual Studio 2015 is required to build it, I use the free Community edition.
More info and binaries: http://ds0.me/csim/
Screenshots of demo circuits:
