Jeux d'orgues is a neat application that contains a number of French organ samples (link here). There's also an iOS version and Android version (called Opus 1). Using a class compliant USB-MIDI adapter or alternatively directly connecting to the USB-MIDI port, it is possible to play the instrument using external controllers.
Here we see it in action with my Yamaha CP-33. The neat thing is the app supports MIDI CC/PC mappings to trigger different stops, which means I can change them using the built in patch keys of the keyboard!
