Last month my mom helped my daughter get a great head start into cleaning the disaster that is her room. Then my daughter ignored the follow up for a month. So this weekend I told her that if she finished cleaning her room, and could keep it that way until her birthday at the end of January, I would get her a cat for her birthday. (She's turning 13, so I think this is a reasonable bribe, it's well within her capabilities to be responsible for a cat) After I told her this, she literally spent all weekend in her room cleaning. Well, I'm pretty sure a good chunk of that time was her getting distracted by anime and YouTube as well, but considering the attention span of 3/4 of this household, it doesn't surprise me.
She is actually taking it seriously for now, but we'll see if it lasts another 2 and a half months.