Someone else mentioned Habitica already, there are a few out there. I think they usually call it gamification. The only one I tried and was able to commit to was Walkscape (specifically gamifying getting out), although I’ve been slacking due to nasty winter weather.

I think what OP is trying to say is that people in their age range will end up being the last of those people, ie. the internet was one of their earliest memories and that happened to be right as it took off. A similar example from my age range, we will probably be the last to remember the WTC attacks. It’s one of the earliest memories I have. Not me specifically, unless I am graced with an incredibly long life, but someone around my age who is.