A variation on the AU teens idea from a while back.
Fandom High the Next few Generation(s). Reverse AU kids meets 20 year reunion meets OH DEAR GOD MY BRAIN. Instead of the AU offspring arriving via ye olde portale, people awake(or go through ze portal) to find themselves in a potential version of Fandom's future where their kids (and possibly those of alumni?) are now students (or even teachers oh noes).
Re: Specific Ideas
Fandom High the Next
fewGeneration(s). Reverse AU kids meets 20 year reunion meets OH DEAR GOD MY BRAIN. Instead of the AU offspring arriving via ye olde portale, people awake(or go through ze portal) to find themselves in a potential version of Fandom's future where their kids (and possibly those of alumni?) are now students (or even teachers oh noes).