Note that certain creative changes were strongly suggested by the listening audience, resulting in stories that almost entirely didn't represent their origin.
Fineas and Pherb - Dr. Dufunschmirtz and his daughter and his 14 children, and his plan of the moment.
Star Wars - Reverse gender Star Wars. These eventually evolved into Star Wars High School, where Prince Luke was constantly chased by Muffy Tarkin, president of the Prince Luke fan club, and her hijinks to make Luke marry her (and so become a princess). Jajar Binks often proved the most valuable backup character. (He was always good for a cheap laugh.)
Equestria Girl - Camping Challenges. The new video (Camp Everfree) isn't even out yet, and I'm already telling stories about it. The girls have seemingly impossible camping challenges, such as camping in lava fields, camping in Time Square, or inserting themselves into movies.
Jenny told other stories. (This had been happening for years. My daughter demands different stories from each of us.)
Final Fantasy X/X-2 - The family comedy of Wakka and Lulu and their four children and their four elemental cats.
Middle Earth - Middle High. In these comedy stories, the characters of Lord of the Rings are now in high school at Middle High, with a running rivalry with the neighboring school, Uruk High. Aragorn is captain of the rugby team, Boromir is the captain of the football team, and Arwen is captain of the cheerleading squad. The hobbits are all freshmen.