Anybody interested in air traffic control simulation?
ATC-pie is a free software program originally designed for multi-player simulation, allowing ATC on the FlightGear network. It now includes a solo training mode, which can create interest outside of FlightGear users.
In this mode, you can select one or more positions to assume between TWR, APP and DEP, and will manage simulated traffic, takeoffs, ILS and visual approaches and landings, entry and exits points, etc. at any airport you would like. It is free software, both as in free beer and in freedom.
Visit the website if you are interested in at least checking out the features. Feedback welcome of course.