There are so many bright and passionate people at CERN, who possess such an immense amount of collective knowledge. It would be a pity not to take full advantage of it. 
For any physics, computer science, engineering-related problem (and many more; these are just examples) you might encounter, there must be at least one person at CERN who has either the solution, or knowledge relevant to the issue. What would it be like if, by means of a mobile app, you could post your problem and get in contact with that person? Or even better, with multiple such people?
The concept of CERNLearn is simple: CERN employees log in, post an issue they would like to discuss with someone else or just a subject they would love to know more about; then the ones who think they can help answer them and then the parts decide upon a meeting date and place, which will be automatically added to their calendars.
As opposed to StackExchange or StackOverflow, where one goes to get online advice from strangers, CERNLearn takes advantage of the proximity and abundance of so many live sources of know-how and focuses on arranging face-to-face meetings. It brings the human factor into learning.
The beautiful thing about it is that it doesn't have to be limited to science. One could hop onto CERNLearn to find natives with whom they could practice a certain language, or, why not, a knitting partner (the first things that came to my mind).
Knowledge and top-class tutoring at the tip of your fingers. By the people, for the people.