As a student, I often read & hear academics meeting in workshops to discuss problems in their fields with their colleagues, or with academics in other field etc.. As a Physics & Mathematics student, I know how beneficial and enjoyable is discussing ideas with a fellow student, so I'm aware of the importance of such meetings.
However, whenever I (with other student) tried to form such a discussion groups, meetings, it always failed. Most of the time, we didn't have any specific problem at hand, and there was nothing to discuss. I mean after all we were learning the subject, and try to understand it; not to solve some particular problem. Of course, one can try to solve some "exercises" as a group, but most of the time those are just to verify we understood what we've learned, and their solutions are in web, so to a Physics/Mathematics students, there is almost no motivation, nor any joy, in solving or talking about them.
Similarly, I've seen various "study groups" in my department (within PhD student, PhD student with his/her advisor etc.) studying some topics together. Up to now, I always did self-studies alone, so knowing that doing this with a second or a third person would be much more beneficial, I also tried to implement such a study group, it also did not work, somehow.
How do academic meetings for discussions & studying managed themselves in a way that it is useful for everyone, much more efficient compare to doing the same thing alone, and enjoyable ?