Commissioned by me from ~arabatos a few months ago, this was partly the result of me re-reading ~simpspin's "Simpson: Generations" comic. I luuuurve the lovey-dovey expressions they all have, especially the girls. In that comic, a 13-year old Maggie and her younger brother, Eric (10 iirc), accidentally fall back through time to the present day.
This picture has nothing to do with that directly, but I did borrow ~simpspin's previous design for teen-Maggie (should've asked him in advance, but thanks to Simpspin for not getting angry that I didn't), and the idea of all the Simpsons meeting up in time and messing up their family's past.
Yes, somehow, all this alteration to the past has not caused any problems with the existences of Bart, Lisa, OR Maggie up in the tree. However Bart and young Marge Bouvier have fallen for each other, as have young Homer Simpson and Lisa Simpson. The young versions of the parents don't know that they're in love with their future kids, and quite frankly no-one else in the scene wants to tell them for their own reasons.
I was going to write this into a fanfic (I like time travel), but...well, it could still happen someday.