Add a computer programming interface
One of the most popular types of online courses are computer programming courses. A lot of online-learning websites (e.g. udacity, codecademy) differentiate themselves in this area because they offer easy-to-use, in-browser code editors where students can write/edit computer programs and have the output of their code validated.
I think that the OpenLearning platform would really benefit to add an equivalent feature. See example interface from codecademy posted.