Pen 13 has 30 year olds playing their teenage selves against actual 14 year olds. Aside from the writing this "gimmick" in itself works and is totally hilarious. It really captures highschool adolescence.

Colin from Accounts is a TV romcom that works. Written by a real life couple playing the romantic leads. They come together over the shared custody of a stray dog that gets injured because the mail lead hits it with his car after the female lead randomly flashes him. Very sweet and touching show.