Me and my friend have started a small group interview program. We provide with daily problems to solve and reading list, daily checkins with details on solution to problems and space/time complexity - this helps with accountability, live weekly sessions with folks from industry and are always available via IM to answer questions or remind for checkins.The reason for starting this group was because our siblings were preparing for their interviews and were dejected/tired/frustrated with the process and lack of structure thereof. We were certain that bringing more people into the program will boost their morale or at least keep it going.Previously we did 2 different groups with average of 10 participants ranging from 2-10 years of experience. 
We expected about 60% of folks to stick to the plan, but 90% ended up finishing 4 weeks of preparations. While number of problems solved is not a true measure of success, by the end of the program everyone had solved at least 60-80 problems.Additionally, we saw participants forming small groups to study together or mock interview each other or explaining their approach.We are starting a new group beginning July 19th.
We are located at  love any thoughts, feedback or any way we can provide value.