I just sent G to clean her room and told her not to come out, except to use the bathroom or get a drink of water, until she's finished. If history is any indicator, this means I won't see her again for three hours, the first two hours and forty-five minutes of which she will spend watching movies and doing time-consuming but nonessential tasks.
Last time we went through this exercise, I suggested that she concentrate on activities that make a visible difference in the tidiness of the room, e.g., making the bed, picking up dirty clothes and shelving books. Instead, when I came in to see how she was doing, I discovered that she had been arranging her DVD cases in alphabetical order. I think this is a ploy to avoid doing any real work by pleading that she's been "cleaning" ALL DAY - never mind that if she tried, she could do the whole thing in 20 minutes and be done with it. I don't expect perfection, just reasonable orderliness and a floor clear enough to vacuum. Sigh.
ETA: In the end, she finished in just over an hour and did a very good job. Color me impressed!