You can also use the bare-bones node-ar-drone module and write your own programs to control the drone. A simple program that gets your drone into the air, rotates it, flips it, and then lands it looks like the following:
3. Intensive Computations and Algorithms
If algorithms, optimization, and performance interest you, there are several websites devoted to coding challenges that range from simple string manipulation to more advanced algorithms. Some popular websites are HackerRank, Coderbyte, and TopCoder.
4. 3D and Virtual Reality
5. Mobile Applications