Effectively this is a way to put a group of items together in a list that you think is worth bundling. So... as I still haven't gotten around to my musical quiz for mortals... Here to help you study is:
The 25 Must have stage musical collection on DVD (save 1)
The short form list is behind the cut with some added notes:
Now there are other Listmania music lists... There's a few I missed. I only had room for 25 and was bound to miss a few that aren't on my list. So, I'll see what else I can add next time.
What did I miss on your list?