I would say no big deal if you let it go that long once or twice, but if the car had 10K mile oil changes all it's life, I would stay away from it.

Like said, drive the car for about 20 minutes, keep it running while you get your oil changing supplies ready, and as soon as you shut it off, change the oil. That is what I do with my cars, and I really think it makes a difference when you change it hot because all of the bad particles are still suspended in the oil.