MultiControl lets you use game controllers for MIDI/OSC

MultiControlFeatures

• Easy to choose any general Human Interface Device (HID)
• Automatically detects buttons, sliders, etc in use
• Automatic scaling to 0.-1. (OSC) or 0-127 (MIDI)
• Easy to choose desired output scaling
• Optional data smoothing
• Can output data using either Open Sound Control (OSC) or MIDI
• Store presets to xml-files

It’s only available as a Mac download at present. Could be fun to play around with. I don’t know how it interfaces with other applications.